Program - INAF - Université Laval

Transcription

May, 12 - 16
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IDF Dairy Science
and Technology
Week / Novalait
Technological
Forum
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Canada
IDF DAIRY SCIENCE AND TECHNOLOGY WEEK 2008
Organizing Committee
Paul Paquin
Chairman, Vice-president FIL-IDF Canada
Pierre Doyle
Assistant Director, Dairy sector, Agriculture and Agri-Food Canada,
Ottawa, Ontario, CANADA
Sylvie Turgeon
Director, STELA Dairy Research Center, Laval University, Québec,
CANADA
Jacques Rolland
Research and Development, Agropur Cooperative, Québec, CANADA
Gaétan Paquette
Senior Director, Finance & Operations, Canadian Dairy Commission,
Ottawa, Ontario, CANADA
Andrée Lagacé
Liaison Officer, STELA Dairy Research Center, Laval University,
Québec, CANADA
Danielle Rivard
General Manager, Novalait inc., Québec, CANADA
Élise Gosselin
Coordinator, Novalait inc., Québec, CANADa
International Scientific Committee
Sylvie Turgeon
Chairman, STELA Dairy Research Center, Laval University,
Québec, CANADA
Milena Corredig
University of Guelph, Guelph, Ontario, CANADA
Daniel St-Gelais
Agriculture and Agri-Food Canada, FRDC, Saint-Hyacinthe,
Québec, CANADA
Ulrich Kulozik
Munchën University, Munchën, GERMANY
Geoff Smithers
Food Science Australia, CSIRO, AUSTRALIA
Philip S. Tong
California Polytechnic State University, USA
Michael Gänzle
University of Alberta, Alberta, CANADA
Paul Jelen
University of Alberta, Alberta, CANADA
Michel Pouliot
Agropur Cooperative, Québec, CANADA
1
PROGRAM AT A GLANCE
MONDAY, MAY 12
TUESDAY, MAY 13
WEDNESDAY, MAY 14
THURSDAY, MAY 15
FRIDAY, MAY 16
A.M.
NOVALAIT
TECHNOLOGICAL
FORUM
P.M.
SESSION 1
SESSION 3
TECHNICAL VISIT:
TECHNICAL VISIT:
Health Properties of Milk and
Dairy products
Microbial Quality of Milk and
New Tools
Kerry Ingredients
Manufacture
Institute of
Nutraceuticals and
Functional Foods
(INAF)
IDF Standing
Committee on Dairy
Science and
Technology Meeting
FIL-IDF Canada
Annual Meeting
LUNCH AND
POSTER SESSION
LUNCH AND
POSTER SESSION
LUNCH AND
POSTER SESSION
NOVALAIT
TECHNOLOGICAL
FORUM
SESSION 2
SESSION 4
Process-Induced Interactions:
Control to Optimize Quality and
Delivery of Health Benefits
Alternatives to Thermal
Processing: Impact on Product
Quality
POSTER SESSION
POSTER SESSION
IDF Action Team
Meetings on Dairy
Science and Technology
AWARDINGS
EVENING
WINE AND CHEESE
Greeting from
Quebec Minister of
Agriculture, Fisheries
and Food
CLOSING DINNER
AND MUSICAL SHOW
The CAPITOLE DE QUÉBEC
FIL-IDF Canada
Annual Meeting
Monday, May 12, 2008
Novalait Technological Forum
9:00 a.m.
FORUM OPENING
Ms. Lorraine BÉDARD, President of Novalait Inc.
Ms. Danielle RIVARD, General Manager of Novalait Inc.
9:15 a.m.
PRESENTATION OF RESULTS AND IMPACTS OF PROJECTS SUPPORTED BY NOVALAIT INC.
Moderator: Mr. René GRIMARD, Agropur coopérative
9:15 a.m.
Control of Oxidation-Reduction Potential in Dairy Processing / Michel BRITTEN
9:35 a.m.
A New Life for Old Starters / Jean-Christophe VUILLEMARD
9 :55 a.m.
Control of Cheese Milk Technological Aptitudes and Monitoring of Microbiological
Activity with Molecular Methods / Gisèle LAPOINTE
10:15 a.m.
Impact Study of Milk Trans Fats on Cardiovascular Risk / Benoît LAMARCHE
10:35 a.m. BREAK – POSTER SESSION AT THE “CARREFOUR DE LA RELÈVE TECHNOLOGIQUE”
11:00 a.m.
Moderator: Mr. Gilbert RIOUX, FPLQ
11:00 a.m. Butyric Spores on the Farm / Pascal DROUIN
11:20 a.m.
Bunker Silos for Grass and Corn / Roger THÉRIAULT
11:40 a.m.
Hay for Dry Cow: DCAD, the solution from Québec! / Sophie LAVALLÉE
12:00 p.m. LUNCH
1:30 p.m.
POSTER SESSION AT THE “CARREFOUR DE LA RELÈVE TECHNOLOGIQUE”
2:00 p.m.
Moderator: Mr. François MARCIL, Laiterie Chalifoux / Les fromages Riviera
2:00 p.m. Breeding and Growth Conditions of Replacement Livestock in Quebec / Roger CUE
2:20 p.m.
2:40 p.m.
3:30 p.m.
Folic Acid, Vitamin B12 and Methionine: Effects on Metabolism and Lactation
Performance / Christiane GIRARD
PREMIUM MILK INNOVATION SPECIAL PRESENTATION
2:40 p.m.
Premium Milk Innovation Project
2007-2015 Scientific and Technological Roadmap
Ms. Élise GOSSELIN, Manager of the Premium Milk Innovation Project
3:10 p.m.
Action Plan for Further Steps
Ms. Danielle RIVARD, General Manager of Novalait Inc.
AWARDING OF THE “PRIX D’EXCELLENCE DE LA RELÈVE TECHNOLOGIQUE”
Ms. Lorraine BÉDARD, President of Novalait Inc. and Mr. Pierre Prémont, CEO of
Quebec Fund for Research on Nature and Technologies (FQRNT)
3:45 P.M.
AWARDING OF THE 2008 MASTER’S EXCELLENCE SCHOLARSHIP FROM THE CANADIAN
DAIRY COMMISSION SCHOLARSHIP PROGRAM, IN COLLABORATION WITH NOVALAIT
INC.
Ms. Lorraine BÉDARD, President of Novalait Inc. and Mr. Gilles Froment, Senior
Director, Policy and Corporate Affairs of the Canadian Dairy Commission
4:00 p.m.
CLOSING ADDRESS
Ms. Lorraine BÉDARD, President of Novalait Inc.
4:15 p.m.
COCKTAIL AT THE “CARREFOUR DE LA RELÈVE TECHNOLOGIQUE” / IDF SCIENCE &
TECHNOLOGY WEEK
2
Forum technologique Novalait
Le lundi 12 mai 2008
9 h 15
Régulation électrochimique du potentiel d’oxydoréduction du lait : impact sur l’efficacité de
transformation et la qualité des produits
Michel BRITTEN1, Claude P. CHAMPAGNE1, Patrick FUSTIER1, Hélène J. GIROUX1,
Monica ARAYA2, Paul ANGERS2, Laurent BAZINET2, Yves POULIOT2,
Jean-Christophe VUILLEMARD2, Jean-Marc CHAPUZET3, Jean LESSARD3,
Marie-Pierre BOLDUC2, Michèle FILION2, Sanaz HARATIFAR2 et Arnaud SCHREYER2
1
Agriculture et Agroalimentaire Canada, Centre de recherche et de développement sur les aliments
(CRDA), 2Centre de recherche STELA – Institut des nutraceutiques et des aliments fonctionnels
(INAF), Université Laval, 3Université de Sherbrooke
L’électroréduction conduit à l’abaissement du potentiel d’oxydoréduction (POR) et de la
concentration en oxygène dissous du lait; l’effet dépend de l’intensité et de la durée du traitement.
L’électroréduction améliore sensiblement la coagulation à la présure des laits chauffés et la stabilité
à haute température. Le traitement n’a pas d’impact sur le développement des flores contaminantes,
mais favorise la survie de certaines souches de bifidobactéries. Les effets de l’électroréduction sur le
lait s’expliquent essentiellement par la diminution de la concentration en oxygène dissous. La
remontée rapide du POR après le traitement, suggère une faible capacité tampon du lait électroréduit
et le rééquilibrage lent des réactions électrochimiques.
9 h 35
Caractérisation des activités biologiques et du potentiel technologique de souches bactériennes
isolées de ferments lactiques naturels
Jean-Christophe VUILLEMARD1, Nadine LACROIX1, Diane GAGNON1, Jocelyn LESSARD1,
Daniel SAINT-GELAIS2, Claude P. CHAMPAGNE2, Jacinthe FORTIN2 et Gaétan BÉLANGER2
1
Centre de recherche STELA – Institut sur les nutraceutiques et les aliments fonctionnels (INAF),
Université Laval, 2Agriculture et Agroalimentaire Canada, Centre de recherche et de
développement sur les aliments (CRDA)
Treize ferments lactiques traditionnels utilisés dans les années soixante ont démontré la capacité de
produire en quantité importante une grande variété de composés aromatiques. La production de
composés aromatiques, comme le diacétyle, a été augmentée par addition de citrate dans les milieux
de préparation des ferments et par le contrôle du pH de propagation. Neuf souches de deux ferments
ont également montré une forte production d’acide gamma-amino-butyrique (GABA), un composé
qui possède des propriétés antihypertensives et calmantes. L’utilisation combinée des 3 bactéries
Lactococcus lactis ssp lactis biovar diacetylactis 74311, S. thermophilus et de Lc. cremoris a permis
d’améliorer la flaveur du fromage en grains tout en réduisant la post-acidification.
3
9 h 55
Pour un meilleur contrôle des aptitudes technologiques du lait de fromagerie
grâce au développement de méthodes moléculaires du suivi
et de la quantification de l'activité microbiologique
Gisèle LAPOINTE1, Denis ROY1 et Daniel ST-GELAIS2
1
Centre de recherche STELA - Institut des nutraceutiques et des aliments fonctionnels (INAF),
Université Laval, 2Agriculture et Agroalimentaire Canada, CRDA
Le présent projet vise à apporter des réponses aux préoccupations des consommateurs, aux besoins
de l’industrie et aux exigences réglementaires en matière de qualité microbiologique du lait et des
produits laitiers. Le premier objectif du projet était d’évaluer des méthodes de contrôle permettant
de prévenir la dégradation de l'aptitude technologique du lait. Les résultats démontrent que le
traitement du lait au dioxyde de carbone ou par la microfiltration peut être utilisé efficacement pour
conserver du lait cru pendant 9 jours à 4 °C. Les fromages produits avec ces laits traités après 9
jours de conservation étaient de qualité comparable à ceux produits avec du lait frais de 2 jours. Le
deuxième objectif de ce projet était de mettre au point des méthodes moléculaires afin d’étudier
l’écologie microbienne des laits avant et après l’application des traitements. Les méthodes ont
permis de déterminer la dynamique et la composition en espèces microbiennes (appelé le
microbiote) du lait, sans culture ni isolement préalable des bactéries. Le troisième objectif du projet
était de développer une méthode pour détecter des déviations dans le comportement des ferments
lors de la transformation du lait. Lors du procédé de fabrication fromagère, la méthode a permis de
déterminer la contribution relative de chacune des trois souches de Lactococcus lactis ssp. cremoris
à l’association en culture mixte et de suivre la modification de l’activité des ferments selon le
traitement. Les connaissances et les techniques sont ainsi disponibles afin d’améliorer la rentabilité
de la production et de la transformation en permettant d’augmenter le temps de conservation du lait
cru avant sa transformation et en identifiant les facteurs de risque qui peuvent compromettre sa
qualité.
10 h 15
Étude de l’impact des gras trans d’origine laitière sur le risque cardiovasculaire
Benoît LAMARCHE1, Paul PAQUIN1, Yvan CHOUINARD1, Simone LEMIEUX2,
Amélie CHAREST2, Johanne MARIN2, Georges COUSINEAU2, Annie MOTARD-BÉLANGER1,
Geneviève GRENIER2, Élise CLERC2, Danielle AUBIN2, Claire JULIEN2, Sandra GAGNON2
Stéphanie OUELLET2 et Patrick COUTURE3
1
Centre de recherche STELA - Institut des nutraceutiques et des aliments fonctionnels (INAF),
Université Laval, 2INAF, Université Laval, 3INAF et CHUQ
Plusieurs études épidémiologiques et cliniques ont associé la consommation d’AGT de sources
industrielles à une augmentation du risque de maladies cardiovasculaires (MCV). D’autre part,
l’association entre les acides gras trans (AGT) d’origine naturelle que l’on retrouve principalement
dans les produits laitiers et le risque cardiovasculaire est beaucoup moins bien documentée.
L’objectif de ce projet était de comparer, dans un contexte nutritionnel contrôlé de façon optimale,
l’impact des AGT industriels et naturels sur les facteurs de risque cardiovasculaire. L’étude clinique
à double insu en chassé-croisé impliquait 38 hommes en santé qui ont consommé 4 diètes
comportant différents niveaux d’AGT naturels et industriels. Les facteurs de risque
cardiovasculaires mesurés à la fin de chacune des diètes ont été comparés. Les résultats ont
démontré que les concentrations plasmatiques de LDL étaient plus élevées à la suite de la diète très
élevée en AGT naturels (10,2 g/2 500 kcal) par rapport à la diète témoin (p=0,03). La diète modérée
en AGT naturels (4,2 g/2 500 kcal) n’a toutefois induit aucun changement significatif dans les
facteurs de risque cardiovasculaires comparativement à la diète témoin. Cette première étude
nutritionnelle contrôlée démontre que la consommation d’AGT naturels pourrait avoir des effets
néfastes sur le profil lipidique, mais que les apports correspondant à la limite maximale pouvant être
consommée par la population semblent avoir des effets neutres sur les lipoprotéines plasmatiques.
4
11 h 00
Développement de stratégies pour diminuer les spores butyriques dans le lait cru
obtenu de vaches nourries à l’ensilage
Pascal DROUIN1, Carole LAFRENIÈRE2, Hani ANTOUN3, Patrice DION3, Gisèle LAPOINTE3,
Marie- Claude JULIEN3 et Annie CHAMPAGNE3
1
Université du Québec en Abitibi-Témiscamingue, 2Unité de recherche et de développement en
agroalimentaire, Université du Québec en Abitibi-Témiscamingue (UQAT), 3INAF, Université Laval
La contamination du lait par les spores butyriques résistantes à la pasteurisation peut entraîner des
pertes économiques de près de 10 millions de dollars/année pour l’industrie fromagère au Québec.
Des recherches indiquent que ce type de contamination est en étroite relation avec l’utilisation
d’ensilage dans l’alimentation des troupeaux. L’approche proposée est d’étudier l’écologie des
Clostridium dans la chaîne de production du lait à la ferme. Parallèlement à ces essais, différentes
stratégies sont explorées pour inhiber le développement des spores. La diminution des spores dans
l’environnement de l’étable devrait se traduire par une meilleure qualité microbiologique du lait
permettant ainsi de réduire les pertes à l’usine. Les résultats ont permis de démontrer qu’il y a deux
profils spécifiques aux Clostridium pour le lait cru sur les fermes. Ces profils ne sont pas constants
pour une même ferme d’une année à l’autre. Les résultats de dénombrement pour les ensilages de
maïs indiquent qu’ils contiennent en moyenne 100 fois plus de spores de Clostridium que les
ensilages d’herbe. Par ailleurs, dans les ensilages de maïs, la production d’acide butyrique
caractéristique du développement des Clostridium est très faible. Dans les silos expérimentaux
préparés à partir de parcelles fertilisées par différentes fumures organiques, les clostridies se sont
développées de façon plus importante dans les ensilages de fléole des prés que dans les ensilages
avec un mélange luzerne/fléole, et ce, malgré le faible nombre de Clostridium lors de l’entrée au
silo. Une bactérie lactique produisant une substance ayant une activité anti-clostridiale a été
identifiée. L’efficacité de cette bactérie a été comparée en silos expérimentaux à un inoculant
commercial ainsi qu’à un produit acidifiant additionné de nitrites.
11 h 20
Ensilages en silos couloir : gestion du remplissage et développement
d’une mesure directe de la matière sèche lors de la préparation
des rations totales mélangées (RTM)
Roger THÉRIAULT1, Philippe SAVOIE2, André AMYOT3 et Luc COUTURE4
1
FSAA, Département des sols et de génie agroalimentaire, Université Laval, 2Agriculture et
Agroalimentaire Canada / Centre de recherche et de développement sur les sols et les grandes
cultures (CRDSGC), Université Laval, 3Institut de recherche et développement en
agroenvironnement, 4Agriculture et Agroalimentaire Canada, CRDSGC
Au Québec, environ 60 % de l’herbe cultivée (sur une superficie de 700 000 ha produisant 4 Mt de
matière sèche par an) et 100 % du maïs-ensilage (environ 40 000 ha et 600 000 t MS) sont conservés
en ensilage, soit 3,0 Mt principalement en silos tour. Au cours des dernières années, le silo couloir
est apparu comme une alternative valable au silo tour. Il pourrait servir à entreposer près de la
moitié des ensilages au Québec d’ici 15 ans. Une bonne conservation en silo couloir exige toutefois
une régie attentive afin de minimiser les pertes et assurer une alimentation de qualité. Une meilleure
information technique (construction, couverture, compactage, reprise) pourrait apporter des gains de
productivité de l’ordre de 4 à 8 $/t MS, soit un potentiel de 6 à 12 millions $ par année pour les
producteurs laitiers quand les silos couloir deviendront plus omniprésents. Le projet de recherche
avait quatre objectifs : 1) préciser la relation entre la densité, la couverture et les pertes; 2) établir le
risque de contamination microbiologique selon la densité et la reprise; 3) établir une relation entre la
densité et la régie lors du remplissage; 4) proposer un système de mesure instantanée de l’humidité
des ensilages pour la préparation de RTM plus précise. Un aspect novateur du projet était
l’intégration de plusieurs éléments de régie et de choix techniques entre le champ et la mangeoire
pour optimiser l’utilisation du silo couloir.
5
11 h 40
Mise à l’échelle de la production et de l’utilisation de foin destiné à la vache tarie
Sophie LAVALLÉE1, Hélène BRASSARD1, Alain FOURNIER2, Guy ALLARD3,
Doris PELLERIN3 et Edith CHARBONNEAU3
1
Agrinova, Centre de services Montérégie, 2MAPAQ Centre-du-Québec, 3 FSAA,
Département des sciences animales, Université Laval
Ce projet consistait en une mise à l’échelle, des résultats d’une recherche scientifique sur la
« production de fourrages adaptés aux besoins de la vache tarie » réalisée de 2002 à 2005 par
l’Université Laval. Il visait à accélérer l’utilisation de cette technique novatrice par l’ensemble des
fermes laitières du Québec. La fièvre vitulaire est la forme clinique d’un désordre métabolique
majeur en production laitière, soit l’hypocalcémie. Les vaches atteintes de fièvre vitulaire produisent
14 % moins de lait lors de la lactation qui suit. Il a été estimé que chaque cas coûte au moins 500 $
en frais vétérinaire et perte de productivité. Pour réussir la période de transition, une ration à faible
différence alimentaire cations-anions (DACA) doit être servie quelques semaines avant le vêlage. Le
projet visait à valider que la production de foin à faible DACA et son intégration à la ration de la
vache tarie, était possible et représentait une approche préventive et efficace pour réduire l’incidence
de la fièvre vitulaire. Dix entreprises laitières des régions du Centre-du-Québec et de la Montérégie
ont été sélectionnées pour leur potentiel à produire un fourrage à faible DACA. À l’été 2006, les
producteurs ont été accompagnés dans la production de foin afin de répondre aux besoins fourragers
des vaches taries. Par la suite, la DACA de la ration des vaches taries a été abaissée entre 0 et 50
mÉq/kg MS, soit en y intégrant le foin à faible DACA (groupe chloré), soit en servant le fourrage
habituel (groupe témoin). Une mesure de l’efficacité du foin a été effectuée grâce à la prise du pH
urinaire avant le vêlage et à des observations comportementales. Les coûts de production du foin à
faible DACA ont été comptabilisés afin de mesurer les impacts économiques d’une telle pratique sur
la ferme. Actuellement, au Québec, peu d’entreprises laitières se prévalent de cette approche
alimentaire novatrice pour réduire l’incidence de la fièvre vitulaire. Il s’agit là d’une excellente
stratégie pour les producteurs laitiers d’utiliser un moyen simple, efficace et naturel et qui s’ajoute
aux ingrédients déjà en place pour réussir une meilleure transition.
12 h 00 - Dîner
13 h 30 - Session d’affiches au « Carrefour de la relève technologique »
Salles Crémazie-Garneau
14 h 00
Conditions d’élevage et croissance des animaux de remplacement du Québec
Roger I. CUE1, Anne-Marie DE PASSILLÉ2, Jeffrey RUSHEN2, Doris PELLERIN3,
Daniel LEFEBVRE4, René LACROIX5 et Kevin Michael WADE5
1
Département des Sciences animales, Université McGill, 2Agriculture et Agroalimentaire Canada,
3
FSAA, Département des sciences animales, Université Laval, 4Valacta, 5Université McGill
Ce projet aborde la problématique de la croissance sous-optimale des animaux de remplacement en
production laitière au Québec, un problème entraînant des pertes estimées à environ 40 millions de
dollars pour l’ensemble des producteurs. Le premier aspect novateur de ce projet est une meilleure
connaissance des profils d’élevage des génisses au Québec, et l’étude des relations entre les profils
d’élevage et la croissance des animaux. Son deuxième aspect novateur est le développement d’un
modèle de croissance des génisses basé sur une approche de modèles mixtes et aléatoires.
6
14 h 20
Interactions acide folique – vitamine B12 – méthionine : effets
sur le métabolisme hépatique et la productivité des vaches laitières
Christiane L. GIRARD1, Hélène LAPIERRE1, Jacques MATTE1, André DESROCHERS2,
Marie-France PALIN1, Carole THIVIERGE3
1
Agriculture et Agroalimentaire Canada, Centre de recherche et de développement sur le bovin
laitier et le porc (CRDBLP), 2Université de Montréal, 3Université Laval
Il est probable qu'une augmentation de la production laitière augmente les besoins en acide folique
et en vitamine B12, ces vitamines intervenant dans les voies importantes des métabolismes protéique
et énergétique. Un apport insuffisant diminuera l'efficacité des voies métaboliques majeures,
augmentant les coûts de production. Les animaux ont un besoin élevé en groupes méthyls, par
exemple, pour synthétiser les membranes cellulaires et celles entourant les gras du lait et stocker
l'énergie dans le muscle. Chez les animaux monogastriques, ces groupes méthyls sont fournis
par la méthionine, la choline et la créatine d'origine alimentaire. Par contre chez les ruminants,
l'alimentation est pauvre en créatine et méthionine, tandis que la choline est détruite par la
microflore ruminale. Pour faire face à l'importante demande en groupes méthyls, les ruminants
doivent donc compter synthétiser ces groupes via le métabolisme des folates et de la vitamine
B 12 . De plus, la vitamine B12 joue un rôle essentiel dans la gluconéogenèse. Le présent projet
visait donc à étudier les effets d'une augmentation des apports en acide folique et vitamine B12, en
présence d'apports adéquats ou insuffisants de méthionine, sur les performances de lactation et les
variables sanguines et hépatiques, indicatrices des voies métaboliques sollicitées pendant les 16
premières semaines de lactation. Les résultats de ces travaux ont permis de démontrer que c’est au
cours des premières semaines suivant le vêlage que les vaches bénéficient le plus des suppléments
de vitamines. Le supplément combiné d’acide folique et vitamine B12 a augmenté la production de
lait et de composantes du lait, surtout en début de lactation, mais cette réponse n’a pas été modifiée
par les apports en méthionine. Les suppléments de vitamine B12 ont augmenté de 50 % le transfert
de cette vitamine dans le lait, augmentation présentant un intérêt nutritionnel non négligeable pour
les enfants en bas âge, les femmes enceintes et allaitantes et surtout, les personnes âgées.
14 h 40 – Présentation spéciale Premium Lait Innovation
Elise Gosselin, directrice du projet
Danielle Rivard, directrice générale, Novalait inc.
15 h 30 – Remise des « Prix d’excellence de la relève technologique »
Mme Lorraine Bédard, présidente, Novalait inc.
M. Pierre Prémont, Président directeur général, Fonds québécois de la recherche sur la
nature et les technologies (FQRNT)
15 h 45 – Remise des bourses d’excellence 2008 / Programme de bourses d’études de la
Commission canadienne du lait en collaboration avec Novalait inc.
M. Gilles Froment, directeur principal, Politiques et affaires corporatives, Commission
canadienne du lait
16 h 00 – Allocution de clôture
16 h 15 – Vin et Fromage
“Carrefour de la relève technologique”
Semaine en science et technologie laitières de la FIL
7
Novalait Technological Forum 2008
Poster session at the “Carrefour de la relève technologique”
1.
Monitoring milk starter activity using a molecular technique – Fabien DACHET,
Université Laval
2.
Milk microbiota dynamics as revealed by molecular techniques – Éric RASOLOFO,
Université Laval
3.
Impact of milk Trans fats on cholesterol metabolism – Geneviève GRENIER, Université Laval
4.
Impact of milk Trans fats on plasmatic lipoproteins – Annie MOTARD-BÉLANGER,
Université Laval
5.
Factors influencing variation of milk components in Québec – Marie-Claude FERLAND,
McGill University
6.
Culture media to study the effect of fatty acids on probiotic growth – Delphine SÈNE,
Université Laval
7.
Impact of a brief dry period on Quebec dairy herds – Débora SANTSCHI, Agriculture and
Agri-Food Canada, FRDC
8.
Brief dry period and mammary gland development – Philippe BERNIER DODIER,
Agriculture and Agri-Food Canada, DRSDC
9.
Brief dry period and feed efficiency – Maude JOLICOEUR, Agriculture and Agri-Food
Canada, DRSDC
10.
Characterization of membranes from fat globule fragments – Jessika BÉDARD-ST-AMAMT,
Université Laval
11.
Effect of heat treatment of cream on cheese processing aptitudes of buttermilk –
Sophie IZMIROGLU, Université Laval
12.
Starch – exopolysaccharids interactions of lactic bacteria from yogurt –
Marie-Claude GENTÈS, Université Laval
13.
Sugar concentration in cheeses – Chantale MORIN, Université Laval
14.
Antibacterial activity of whey protein hydrolysates – Émilie TURGEON, Université Laval
15.
Detection of lactic bacteria phages in the air – Daniel VERREEAULT, Université Laval
16.
Cheddar cheese bacteria: abundance or activity? – Émilie DESFOSSÉS-FOUCAULT,
Université Laval
17.
On the Camembert trail: leading edge techniques to uncover its metagenome –
Marianne ARTEAU, Université Laval
18.
Survey on cheddar cheese quality: the microbial community under interrogation! –
Sadjia RACHEK, Université Laval
19.
Subclinical mastitis: prevent or treat infections? – Simon DUFOUR, Université de Montréal,
Faculté de Médecine Vétérinaire
20.
Virulence factors of S. aureus associated with chronic mastitis in Canada –
Bich VAN LE THANH, Université de Montréal, Faculté de Médecine Vétérinaire
8
IDF DAIRY SCIENCE AND TECHNOLOGY WEEK
MAY 12 – 16, 2008, QUEBEC, CANADA
SESSION 1 – Tuesday, May 13, 2008
Health Properties of Milk and Dairy Products
8:45 a.m.
INVITED SPEAKER
Trans Fatty Acids and Cardiovascular Disease: An Update on Naturally
Occurring Trans Fat?
Dr. Benoît LAMARCHE
STELA Dairy Research Center / Institute of Nutraceuticals and Functional Foods
(INAF), Université Laval, Québec, CANADA
Trans fatty acids (TFA) in foods have recently attracted worldwide attention, owing to their
undesirable effects on human health. In Canada, it has been estimated that TFA intake in 1995
averaged 8.4 g/day, which was equivalent to approximately 3.7% of the total energy intake in adults.
When combined altogether, data from epidemiological studies indicated that an increase in TFA
intake equivalent to 2% of daily energy was associated with a significant 25% greater risk over time.
These data also indicated that on a gram to gram basis, TFA had a 10 times greater impact on the risk
of CVD than SAT fat, suggesting that the impact of TFA on the cardiovascular health goes far
beyond its effect on cholesterol levels. Although small in relative terms, the proportion of total
dietary TFA coming from “natural” sources (mostly ruminant milk and meat) is not trivial. In fact,
this proportion can be as high as 90% in countries where TFA from industrial sources have been
eliminated. While the intake of TFA from industrially hydrogenated vegetable oils (iTFA) is now
well known to have a deleterious impact on cardiovascular health, the effects of TFA from ruminants
(rTFA) are virtually unknown. This presentation will summarize the results of two recent clinical
studies that have compared the impact on dietary iTFA and rTFA on cardiovascular risk factors. In
women, iTFA lowered HDL cholesterol, LDL cholesterol, and triacylglycerol concentrations
compared on a gram to gram basis with rTFA. On the other hand, dietary rTFA seem to have the
same effects on plasma LDL cholesterol levels as iTFA in men. However, our own studies indicate
that at a dietary intake achievable in “real life”, rTFA are very unlikely to have any effect on most
cardiovascular risk factors. These data, along with earlier evidence from epidemiological studies
suggest that TFA from ruminants sources are unlikely to be harmful from a heart health perspective.
Benoît Lamarche is professor at the Department of food science and nutrition at Laval University.
He also is chair of the Canada Research Chair in Nutrition, Functional Foods and Cardiovascular
Health since 2001. Dr. Lamarche completed a bachelor’s degree in Biochemistry (1991). He carried
on graduate studies in Physiology at Laval University (1996) and postdoctorate training at the
Faculty of medecine of the University of Toronto (1998). His research concentrates mainly on
nutrition, functional foods and their impact on cardiovascular health.
9
SESSION 1 – Tuesday, May 13, 2008 (cont’d)
9:30 a.m.
Antiviral Activity of Esterified Whey Proteins
Jean-Marc CHOBERT1, Mahmoud SITOHY1, 2, Sylviane BILLAUDEL3, Michèle
DALGALARRONDO1, and Thomas HAERTLE1*
1
UR Biopolymères interactions assemblages, INRA, Nantes, Équipe fonctions et interactions des
protéines laitières, Nantes, 2Université de Zagazig, Faculté d’Agriculture, Département de
biochimie, EGYPTE, 3Université de Nantes, UFR des sciences pharmaceutiques, bactériologievirologie, Nantes, FRANCE
Esterification is a simple and cheap reaction without production of harmful secondary products.
Depending on its extent, it produces proteins/peptides positively charged with a polycationic
character, able to interact with polyanionic substances. Interactions between esterified milk whey
proteins (beta-lactoglobulin, alpha-lactalbumin) transformed in polycations and (i) polyanionic
molecules of DNA or (2) virus directed against Lactocoques used in dairy industry have been
demonstrated previously. Recently, we have shown that such modified whey proteins can inhibit the
replication of several viruses such as Herpes simplex virus, cytomegalovirus, poliovirus type-1, or
Coxsackie virus B6. The antiviral activity of esterified whey proteins (IC50 = 20-40 µg mL-1)
observed against virus infecting Vero cells depended on five factors (in order of importance):
concentration of esterified proteins, multiplicity of infection, duration of incubation, timing of
esterified proteins addition after infection, and extent of esterification of proteins. The relative
amounts of viral RNA were less affected by the esterified proteins concentration than was the virus
infectious titer, indicating that inhibitory proteins may slow down viral multiplication, yielding
reduced amounts of viral RNA. Hence, we can propose a new product enhancing surface sterilisation
in food and bio-technologic industries susceptible to viral infections. Such a product could be
incorporated in detergents used in the surface treatment in industry, hospitals, household and for
cutaneous treatment. It could be used also as one of the elements of defence of agro-production and
human means against deliberate infections (agro-terrorism, bio-terrorism) and against accidental
infections.
10:00 a.m.
Health Promoting Properties of Fermented Buttermilk.
Brian A. MURRAY* and Philip M. KELLY
Moorepark Food Research Centre, Teagasc, Moorepark, Fermoy, Co. Cork, IRELAND
The milk fat globule membrane (MFGM) is increasingly recognised to possess important
biologically active protein and phospholipid components. MFGM biologically active lipids include
structural components of membranes and lipoproteins and function as signalling molecules in
processes such as regulating cell growth and cross membrane trafficking. Certain sphingolipids are
known to influence apoptotic pathways, and their anti-cancer effects may lead to potential
constituents in an anti-cancer regime. In addition, studies on intestinal digestion of milk have
identified a sphingomyelinase activity which degrades sphingomyelin into sphingosine and ceramide
both of which are potent anticancer agents. Considerable progress is being made in recent years with
regard to the measurement and characterisation of MFGM components in buttermilk and other dairy
product sources. However, little work has been done in relation to the role of fermentation on the
composition and biological activity of MFGM. Fermentation is applied in the course of dairy product
manufacture while bacterial growth and metabolism also takes place in vivo following ingestion.
Hence, a study has been initiated which aims to examine changes that occur during fermentation of
buttermilk containing MFGM by selected lactic acid bacteria. The objective, therefore is to examine
whether the various forms of fermentation have a beneficial effect in enhancing the biological
activity of MFGM-based components and extracts.
10
11:00 a.m.
Randomized Controlled Trial Comparing the Bioavailability of Vitamin D3 from Fortified
Cheddar Cheese, Fortified Low-Fat Cheese, and Supplement
Dennis WAGNER*, Gloria SIDHOM, Susan J. WHITING, Dérick ROUSSEAU,
and Reinhold VIETH
Department of Nutritional Sciences, University of Toronto, Department of Pathology and
Laboratory Medicine, Mount Sinai Hospital, Toronto, CANADA
There is a need to increase the options for vitamin D fortification. We have developed a method to
fortify hard cheeses with vitamin D3. We compared the bioavailability of vitamin D3 from fortified
hard cheeses and from a well-characterized liquid vitamin D3 supplement. Sixty adults were
randomly given weekly servings of fortified full-fat Cheddar cheese (34 g), fortified low-fat cheese
(41 g), or vitamin D3 supplement. These contained 28,000 IU vitamin D3, equivalent to 4,000 IU/d.
20 adults were also randomized to placebo. Bioavailability of vitamin D3 was assessed by comparing
the serum 25-hydroxyvitamin D [25(OH)D] response over 8 weeks. In the placebo group, initial
serum 25(OH)D, 55.0 ± 25.3 nmol/L (mean ± SD), declined over the 8-week winter protocol, to 50.7
± 24.2 nmol/L (paired t test, p=0.046). In the vitamin D3-treated groups, the mean increases in serum
25(OH)D from baseline to 8 wk were: 65.3 ± 24.1 nmol/L (Cheddar cheese), 69.4 ± 21.7 (low-fat
cheese), 59.3 ± 23.3 (supplement with food), and 59.3 ± 19.6 nmol/L (supplement without food);
these changes were significantly different from the placebo group (ANOVA, p<0.0001) but not from
one another (ANOVA, p=0.62). Compared with baseline, serum parathyroid hormone decreased
significantly with both the fortification (paired t test, p=0.003) and the supplementation (paired t test,
p=0.012) strategies. Vitamin D3 is equally bioavailable from fortified hard cheeses and from
supplement. Therefore, hard cheese is a viable food for vitamin D fortification, and can help to
enhance vitamin D.
11:30 a.m.
Caseinphosphopeptides and Calcium Absorption from Bovine
and Caprine Calcium-Fortified Fermented Milks
Adela MORA-GUTIERREZ1*, Miguel MORA-GUTIERREZ 2, and Changzheng WANG3
1
Cooperative Agricultural Research Center, Prairie View A&M University, TX, 2Department of
Gastroenterology, Universidad Central de Venezuela, Caracas, VENEZUELA, and 3Human
Nutrition Research, Kentucky State University, Kentucky, USA
In an effort to improve calcium (Ca) status, some investigators have focused on finding food
ingredients that might enhance calcium absorption and/or utilization. Caseinphosphopeptides (CPP)
are released from the proteolytic digestion of casein during food processing or gastrointestinal
digestion. CPP prevent the formation of insoluble Ca salts thereby increasing the bioavailability of
Ca in the ileum or the distal small intestine. Four major casein components are present in casein of
bovine milk: αs1-, αs2-, β-, and κ-casein. However, in caprine milk there is a high degree of variance
in casein proportions among animals, which appears to be genetically controlled. The ability of CPP
prepared by enzymatic hydrolysis from the respective caseins (extrinsic CPP) to enhance Ca
absorption from bovine and caprine Ca-fortified fermented milks was compared with intrinsic CPP
released from the gastrointestinal digestion of caseins to enhance Ca absorption. Growing male
Sprague Dawley rats were randomly assigned (7/group) to receive bovine and caprine Ca-fortified
fermented milks alone or enriched with CPP (1 mg/ml). An aqueous solution of the bovine and
caprine Ca-fortified fermented milks (10% w/v) labeled extrinsically with 45Ca was given by gastric
intubation. Absorption was determinated from measurements of radioisotope activity in femur.
Addition of CPP enhanced Ca absorption from Ca-fortified fermented milk. Ca absorption was less
pronounced in Ca-fortified fermented milk without added CPP. Based on the results of this study we
can conclude that the addition of CPP have beneficial effect on the absorption of CaCO3 added to
bovine and caprine fermented milks.
12 NOON – LUNCH - POSTER SESSION: Rooms Crémazie – Garneau, and Hall
11
SESSION 2 – Tuesday, May 13, 2008
Process-Induced Interactions: Control to Optimize Quality and Delivery of
Health Benefits
1:30 p.m.
INVITED SPEAKER
Dairy Components and Products for Weight Management
and Metabolic Syndrome
Riina KEKKONEN
Valio Ltd, R&D and University of Helsinki, Institute of Biomedicine, FINLAND
Metabolic syndrome is a cluster of metabolic disorders which are risk factors for
cardiovascular disease and type-2 diabetes. These risk factors include obesity,
hypertension, dyslipidemia and impaired glucose tolerance. Abdominal obesity and insulin resistance
are thought to represent common underlying factors of the metabolic syndrome, which features also a
chronic low-grade inflammatory state. Genetic factors have an influence on the development of
metabolic syndrome, but lifestyle and health behaviour have a great impact on the progress as well as
the development of metabolic syndrome. The key recommendations for the prevention and
management of metabolic syndrome include promotion of healthy lifestyle through weight loss,
change in dietary composition, and increase in physical activity.
There is emerging evidence that dairy products could have protective effects against obesity and
metabolic syndrome. In epidemiological studies, high dairy calcium intake is associated with lower
weight. High calcium intake from milk products seems both to prevent weight gain and to improve
the results of dieting. A strong reverse correlation has been observed between regular and high
consumption of milk products and the development of metabolic syndrome and type-2 diabetes in
adults. The underlying mechanism of action is still unclear but it is most probably related to milk
proteins. Also other components may contribute to the beneficial effects. Whey protein has been
investigated for its satiety increasing and insulinotropic properties. Dairy protein and calcium has
been linked to improved body composition. In addition, peptides, calcium and other minerals may
have blood pressure lowering effects. Recently, intestinal microbes have been linked with obesity
which may have potential therapeutic implications through modulation of the gut microbiota with
fermented or probiotic products.
In recent years a number of products designed to help in weight management have been launched.
Increasingly, these are positioned as making the consumer feel fuller for longer and therefore cutting
down on hunger between meals and helping to avoid snacking. This satiety trend features new
products with combinations of fibre and protein, fibre on its own or different branded ingredients.
Indeed, the food industry possesses a central role in the solution of the obesity and metabolic
syndrome problem. It is obviously not solved entirely by the action of the food industry, but the
whole society has to be involved. And still, the individuals themselves make the final choices.
Successful life style changes in terms of diet require sensible daily choices of foods and drinks,
which can be supported by the expertise of the food industry.
Riina Kekkonen works as a research scientist at Valio Research Centre, Finland since 2001. She is
responsible for planning, conducting and coordinating experimental and clinical studies. Her main
research concern the effect of probiotics on immune response, health effects of dairy proteins and
weight management. She obtained her Master’s degree (Health Sciences, Nutrition) at Kuopio
University. Besides her work at Valio Research Centre, she is at the moment finalizing her PhD
studies at the University of Helsinki, Faculty of Medicine, Institute of Biomedicine, on the topic
“Immunomodulatory effects of probiotics” (cellular and clinical studies).
12
Health Benefits
2:15 p.m.
Effects of Caseins on the Thermal Stability of β-Lactoglobulin
Yie Hui YONG* and Allen E. FOEGEDING
Department of Food, Bioprocessing, and Nutrition Sciences,
North Carolina State University, USA
Casein fractions have been shown to act as molecular chaperons and inhibit aggregation of whey
proteins in dilute solutions (<1% w/v). The goal of this investigation was to determine if this
approach is a viable way to stabilize higher concentrations of proteins as desired for beverage
application. Mixtures of β-lactoglobulin (6% w/v) and either β-casein (0.01 to 2% w/v) or α-casein
(2% w/v) were adjusted to pH 6.0 and heated (70 to 90°C) for 20 min, cooled then analyzed to
determine the aggregation degree. Overall aggregation was determined by solution turbidity (optical
density at 400 or 600 nm). Soluble aggregate mass and radius of gyration were determined by multiangle laser light scattering (MALLS). Addition of 0.05% (w/v) β-casein or greater caused a drop in
turbidity. In contrast, inhibition was not observed when 2% (w/v) α-casein was added. Moreover,
prolonged heating (60 min) of β-lactoglobulin with 2% (w/v) β-casein (pH 6.0) at 90°C produced a
clear solution while β-lactoglobulin solutions containing α-casein formed semi-turbid gels after
heated for 15 min. MALLS measurements confirmed the turbidity results. For instance, at 75°C,
solutions containing 2% (w/v) β-casein and 6% (w/v) β-lactoglobulin produced aggregates with
lower molar mass (80% in the range of 3.0x106 to 2.0x107 g/mol) and smaller radius of gyration
(80% in the range of 19 to 30 nm) as compared to their control cohorts (3.5x107 to 7.0x108 g/mol and
58 to 85 nm, respectively). These results show that β-casein is a feasible component to stabilize
higher concentration whey proteins in beverages.
2:45 p.m.
Gelation of Undenatured Milk proteins by Interaction with Anionic Polysaccharides
and its Potential Applications
Sandra I. LANEUVILLE1* and Sylvie L. TURGEON1
1
STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF),
Université Laval, Québec, CANADA
The gelation of three different milk proteins, β-lactoglobulin, BSA and sodium caseinate was
achieved by electrostatic interaction with different anionic polysaccharides (xanthan gum, λcarrageenan). The uniqueness of this work resides in that no thermal, enzymatic or any other
denaturing treatment was applied to the protein or the mixture at any time. Gelation was induced by
in-situ acidification to a pH where both molecules carry net opposite charges, resulting in a
tridimensional network stabilized by the electrostatic attractive interactions between both molecules.
Our studies showed that this gel could be formed in a wide range of protein to polysaccharide ratios,
ionic strengths, and concentrations (including extremely low concentrations ~ 0.03-3 wt%),
depending on the studied macromolecules. The kinetics of gel formation was followed by dynamic
rheology, microscopy and in some cases, by static light scattering. It was found that the gels were
composed of aggregated complexes of a fractal nature (fractal degree ranging from ~ 2.1-2.4).
Moreover, our results demonstrate the great impact that the molecular charge density and
conformation had on the gel strength and its internal structure, with globular and more charged
proteins forming stronger and denser gels than random coil proteins. Interestingly, some gels were
more stable at higher ionic strengths, due to charge shielding, which diminished the strong
electrostatic interaction, thus preventing syneresis. Potential applications are being studied, e.g., in
milk systems, where understanding the molecular factors leading to this type of interaction is
essential to fully grasp the role of bacterial exopolysaccharides in the structuration of products such
as yoghurt. Other studies include the use of this gel as a vehicle for liposomes that could eventually
be used to protect/transport delicate molecules such as enzymes, nutraceuticals or drugs.
13
Health Benefits
3:45 p.m.
Relation Between Physical State and Survival of Freeze-Dried Probiotic Bacteria.
Lone KURTMANN*, Charlotte U. CARLSEN, Leif H. SKIBSTED, and Jens RISBO
Food Chemistry, Department of Food Science, Faculty of Life Science, University of Copenhagen,
Frederiksberg, DENMARK
The composition of freeze-drying medium for probiotics is important in relation to stability and
survival of the bacteria during storage. The drying process removes water, and the matrix
components, mainly carbohydrates, serve to embed and protect the bacteria in the dry state. During
dehydration under suitable conditions, high concentrations of carbohydrates will form an amorphous
glassy matrix, which is characterised by an extremely high viscosity. In a glassy matrix the molecular
mobility is lowered due the high viscosity, and consequently the rates of detrimental reactions in a
bacteria culture should be limited. Dried bacteria are suggested to be protected during storage if the
they are stored below the glass transition temperature, Tg, and in the current study we have
constructed two water activity-temperature state diagrams, one for each of two different matrices
embedding the probiotic bacteria Lactobacillus acidophilus. The state diagrams map the changes in
the physical state of the freeze-dried bacteria cultures in relation to storage temperature and water
activity, and based on this information it was possible to investigate directly the relation between the
physical state of the dried cultures and the bacteria survival during storage. The results show that
careful selection of temperature and water activity for storage of dried probiotics is important, but
also that detrimental reactions cannot be fully eliminated by storage in glassy states.
4:15 p.m.
Does Milk Processing Influence Casein Digestibility in Infant?
Didier. DUPONT1*, A. Mackie2, D. Molle1, J. Leonil1, and E.N.C. Mills2
1
INRA – UMR Science et technologie du lait et de l’oeuf, Rennes, FRANCE
2
Institute of Food Research (IFR), Colney, Norwich UNITED KINGDOM
Bovine milk proteins are the first non-human proteins consumed by the infant, after or instead of
breast-feeding. Among them, caseins are the major ones and due to their flexible structures are
known to be extremely sensitive to digestion, leading to the formation of peptides that may have
positive (anti-hypertensive, immunomodulatory, opioid) as well as negative (allergenic) effects on
infant health. Processing may have a significant impact on casein structure. For instance, heattreatment is known to enhance protein–protein interactions generating supramolecular structures like
aggregates. The objective of this work was to determine if processing could make caseins more
resistant to digestion using a physiologically relevant in vitro model mimicking the infant gut and to
determine the protein region that showed resistance to digestion. Sixteen well-defined and differing
casein-containing matrices (purified caseins, micelles, raw, pasteurized and sterilized milks,
yogurts…) were submitted to in vitro digestion using an infant gut model. Digested samples were
analysed by SDS-PAGE, RP-HPLC and indirect ELISA using polyclonal antibodies. Four digested
samples (raw, pasteurized, sterilized milks and yogurt) were further characterized using 25 different
monoclonal casein-specific antibodies and LC-MS-MS. Large fragments were found resistant to
digestion and corresponded to the areas β-CN(f76-93), κ-CN(f98-169), αs2-CN(f36-75) and αs1CN(f149-199) to a lesser extent. These sequences corresponded to hydrophobic areas of the caseins
at pH 3.0, i.e. the pH used during the gastric phase. Comparison of the short peptides patterns
showed that processing of raw milk into sterilized and yogurt led to a higher resistance of casein to in
vitro digestion.
4:45 p.m.: POSTER SESSION: Rooms Crémazie – Garneau, and Hall
14
SESSION 3 – Wednesday, May 14, 2008
Microbial Quality of Milk and New Tools
8:30 a.m.
INVITED SPEAKER
Probiotics vs Gastrointestinal Infection
Dr. Mansel GRIFFITHS
Department of Food Science and Canadian Research Institute for Food Safety,
University of Guelph, Ontario, CANADA
Many dairy products containing pre- or probiotics are appearing on the market that
purport to be good for you. However, the scientific basis for these health claims
has been limited. It is only in recent years that the mechanism of action of
probiotics has been investigated and many of their beneficial health effects substantiated. For
example, many studies have shown that probiotics protect against gastrointestinal infection and it has
been thought that this is mediated by competition between probiotic microflora and pathogens for
intestinal colonization sites and stimulation of the host’s immune system. We have recently shown
that probiotics also produce bioactive molecules that down-regulate virulence genes in enteric
pathogens and this effect may be mediated through interference of cell-cell signalling pathways.
These molecules have the potential to be used as prophylactics to prevent foodborne infections and
will provide the industry with opportunities to develop “designer foods” targeting certain sectors of
the population most at risk of foodborne infections.
Dr. Mansel Griffiths is senior chairholder since 1991 of the DFO/NSERC Senior Industrial Research
Chair in Dairy Microbiology. His research team is engaged in research to develop detection methods
for foodborne microorganisms and to learn more about how microorganisms behave in food and food
production/ processing environments. They are leaders in the application of bioluminescence for the
study and detection of foodborne microorganisms which allows to study organisms in vivo without
recourse to culture. They have developed diagnostic methods for the detection of foodborne
pathogens that can be applied directly in foods. They also have developed novel methods for using
bacteriophage to detect foodborne pathogens which are being commercialized. There is substantial
interest in the development of phage as antimicrobial agents for use in human and veterinary
medicine. They also have the potential for controlling contamination at food processing facilities.
15
SESSION 3 – Wednesday, May 14, 2008 (cont’d)
9:15 a.m.
Screening of the Proteolytic Psychotrophic Flora in Raw Milk: Does the Role
of Pseudomonas Fluorescens Need Revision?
Sophie MARCHAND*, Kim HEYLEN, Katleen COUDIJZER, Paul DE VOS,
Koen DEWETTINCK, Jan DE BLOCK, and Marc HEYNDRICKX
Institute for Agriculture and Fisheries Research Technology & Food, Melle, BELGIUM
Proteolytic psychrotrophs, particularly Pseudomonas, are the key microorganisms responsible for
spoilage of milk and dairy products, due to their ability to produce heat-resistant proteases. To
investigate the psychrotrophic heat-resistant proteolytic activity in raw milk, 86 raw milk samples
were screened. 103 proteolytic strains isolated and identified to species level using API 20NE. 91.3%
of the isolates belonged to Pseudomonas. Consistent with literature data, 50% of the isolates were
identified as P. fluorescens according to API 20NE. Although API tests are frequently used for rapid
identification of microorganisms, they have limited taxonomic resolution for certain Pseudomonas
species groups. As DNA-based techniques have provided more reliable approaches to bacterial
identification and differentiation at the species level, a (GTG)5-PCR was performed as screening
method. The fingerprints displayed a large genetic diversity in the isolated strains on species and
infraspecific level. Nevertheless, these data revealed two major clusters representing isolates with
great milk spoilage potential. For a polyphasic identification approach, 29 representatives were
subjected to Fatty Acid Methyl Ester, 16S rDNA and rpoB sequence analysis. The first two
techniques appeared not discriminatory enough to identify Pseudomonas isolates to species level. On
the other hand, rpoB analysis identified the main spoilers in our milk screening study as
Pseudomonas fragi and Pseudomonas lundensis. These results were confirmed by DNA-DNA
hybridisation. Moreover, Pseudomonas fluorescens appeared to play a minor role in the investigated
samples. Misidentification in the past due to biochemical testing systems and the absence of a
polyphasic approach could probably partly explain why Pseudomonas fluorescens appears to be such
a heterogeneous species and why its role in milk spoilage has probably been overestimated.
9.45 a.m.
Differences in Heat Resistance and Growth Limits of Listeria monocytogenes Strains,
and Identification of Potential Biomarkers
Stijn VAN DER VEEN1,2*, Roy MOEZELAAR2, Jeroen WOUTERS1, Tjakko ABEE2,
and Marjon H. J. WELLS-BENNICK1,2
1
NIZO Food Research, Division Health & Safety, Ede, The Netherlands, 2Top Institute Food and
Nutrition (TIFN), Wageningen, THE NETHERLANDS
Listeria monocytogenes is a foodborne pathogenic bacterium which is the causative agent of
listeriosis. Due to the severity of the disease and the fact that its incidence is increasing in numerous
european countries, L. monocytogenes is of great public health concern. Food manufacturers,
including those producing dairy products containing unpasteurized milk or ready-to-eat foods, have
had to re-evaluate their processes in order to maintain safe food products. One of the most important
strategies to reduce the incidence of food-borne listeriosis is to prevent growth to high numbers in
the case of contamination. We assessed the growth limits and heat resistances of a large number of
L. monocytogenes strains (total 138) of different origins of isolation and serotypes. Significant
differences in heat resistance was observed between strains. Furthermore, growth was evaluated
using combinations of low pH, sodium lactate, and high salt concentrations in BHI broth at different
temperatures. We found that serotype 4b strains, which are most commonly isolated in cases of
clinical listeriosis, have the highest acid and salt tolerance at 30 °C. The highest tolerance for high
NaCl concentrations was found for serotype 1/2b strains at 7 ºC, at neutral pH and pH 5.5. The
association of certain L. monocytogenes serotypes with particular stress responses likely reflects
adaptation to specific niches, possibly explaining the abundance of certain types in foods and others
in clinical cases. We were furthermore able to identify specific genes associated with particular
phenotypes, which may be candidate genes to be used as suitable biomarkers for specific L.
monocytogenes strains in foods.
16
SESSION 3 – Wednesday, May 14, 2008 (cont’d)
10:45 a.m.
A Toolbox to Quantify Enterotoxin Gene Expression in a Complex Microbial Ecosystem
Manon DUQUENNE1,2*, Marina AIGLE1, Isabelle BATAILLON1, Pascal QUENEE1,
Tiphaine LEROY, Elise BOREZEE-DURANT1, Sylviane DERZELLE2,
Véronique DEPERROIS-LAFARGE2, Marielle BOUIX3, and Agnès DELACROIX-BUCHET1*
1
INRA, Unité bactéries lactiques et pathogènes opportunistes, Jouy-en-Josas, 2Agence française de
sécurité sanitaire des aliments, Laboratoire d’études et de recherches sur la qualité des aliments et
des procédés agro-alimentaires, 3AgroParisTech Massy, Massy, FRANCE
Cheese is a complex and dynamic microbial ecosystem characterized by the presence of a large
variety of bacteria, yeasts and moulds. Some microorganisms, including species of lactobacilli or
lactococci, are known to contribute to the organic quality of cheeses, whereas the presence of others
may lead to spoilage or constitute a health risk. Staphylococcus aureus is recognized worldwide as
an important foodborne pathogen, owing to the production of enterotoxins in food matrices. In order
to study enterotoxin gene expression during cheese manufacture, we developed an efficient method
to recover total RNA from cheese and a robust method to study gene expression by quantitative RTPCR. RNA is isolated from cheese in two steps: A cheese sample is first homogenized in citrated
water with a mechanical blender and cells are isolated by centrifugation. Cells are then disrupted and
total RNA is purified using a classical protocol. This method yields pure preparations of undegraded
RNA accessible for RT-PCR. It is important that quantitative RT-PCR data be normalized with a
proper internal control to obtain reliable results with biological significance. We thus investigated the
expression stability of ten housekeeping genes potentially useful as references in studies of S. aureus
grown in milk or cheese, using the geNorm Visual Basic Application for Microsoft Excel.
Enterotoxin gene expression can therefore be normalized using the geometric mean of the three most
stably expressed reference genes. And gene expression is correlated with enterotoxin quantity.
11:15 a.m.
Development of Antibody Microarray-based Biosensor for Bacterial Detection
Isabelle NOISEUX1*, Jean-Pierre BOUCHARD1, Fabien CLAVEAU1, François BABIN1,
François ROY-MOISAN1, Marci VERNON1, and Shu CHEN2
1
Institut National d’Optique (INO), Québec, 2Laboratory Services Division,
University of Guelph, Ontario, CANADA
The detection, identification and quantification of different pathogenic microorganisms
simultaneously at low cost are of great interest to the agrifood industry. This paper describes the
development of a low cost biosensor based on antibody microarrays. The biosensor is a LED-based
microarray reader that uses imaging processing algorithms to improve the signal-to-noise ratio over
that of commercial readers. Proof-of-concept tests were carried out with Salmonella and
demonstrated detection of 105 CFU in less than 2 hours with no interference by the presence of other
bacteria in the sample. Results from an overnight enriched-sample showed the detection of 10 CFU
of Salmonella in 25g of a Salmonella-inoculated food sample. These results are compared to those
obtained with a commercial microarray reader and show equal to better performance. The developed
biosensor is a low cost solution for simultaneous detection of different types of bacteria or other
organisms of concern in complex food samples.
11:45 LUNCH - POSTER SESSION: Rooms Crémazie – Garneau, and Hall
17
SESSION 4 - Wednesday May 14, 2008 p.m. (cont’d)
Alternatives to Thermal Processing:
Impact on Product Quality
1:30 p.m.
Non-Thermal Processing Technologies and Dairy Product Quality
§
Dr. Geoffrey W. SMITHERS* ,
Cornelius (Kees) VERSTEEG, and Jay SELLAHEWA
Food Science Australia, New South Wales, AUSTRALIA
In the 21st century, innovation and product differentiation in the dairy industry
will be essential in enhancing international competitiveness in a truly global
food marketplace. Such innovation and differentiation will also be critical in meeting consumer
demands for so-called ‘miracle foods’ that are not only safe and nutritious, but also natural,
promote health and well-being, great tasting, convenient, economical to manufacture,
environmentally-friendly, and individually tailored for each consumer. These marketplace
drivers create quite a challenge to the dairy industry who must ‘think outside the traditional
box’, often to new and novel approaches that when adapted and applied in dairy systems will
result in innovation, differentiation, and consumer excitement and acceptability. Several nonthermal processing technologies, notably ultra-high pressure, power ultrasonics, and pulsed
electric field, are creating an impact in agri-food processing around the world. While these
technologies have been largely viewed as alternative non-thermal techniques to enhance
microbiological safety and quality of food streams and products, they are increasingly being
developed for a range of other applications in dairy systems, including (a) improved processing
effectiveness and enhancement of quality; (b) differentiation of ingredients and products
including tailored functionality, both physical, nutritional and organoleptic; (c) preservation of
unstable bioactive ingredients; (d) modulation of enzyme activity; and (e) hypoallergenic
ingredients and products. In this presentation, the potential of the major non-thermal processing
technologies in dairy systems will be introduced, together with an examination of their current
and potential applications in processing and modulating dairy streams and products. The
presentation will explore the science underpinning the observed effects, and how this
understanding can accelerate and strengthen commercialization of these non-thermal dairy
processes, and capture benefit for the dairy industry.
Dr. Geoffrey Smithers is the Director of Australia's Commonwealth Scientific and Industrial
Research Organisation (CSIRO). He is responsible for setting the strategic framework for
relationship and business development in international markets, and directing and coordinating
activities in these markets. Dr. Smithers has a background in both fundamental and applied
R&D in the areas of advanced processing and ingredient functionality, together with 'hands-on'
experience in food business practice. He published plentifully in scientific literature and
invented several patented applications.
18
2:15 p.m.
High Pressure Homogenization as Alternative to Thermal Treatment to Improve the Microbial
Safety, Shelf-Life and Functionality of Milk and Milk Products
Maurice NDAGIJIMANA, Francesca PATIGNANI*, Lucia VANNINI, Pamela VERNOCCHI,
Rosalba LANCIOTTI, and M. E. GUERZONI
Alma Mater Studiorum, University of Bologna, Department of Food Science
Bologna, ITALY
Novel non-thermal processes represent an alternative to thermal treatment to improve quality, safety
and functionality of milk and milk-based products. Among the alternatives proposed, the “highpressure homogenization” (HPH) is one of the most promising technologies and its potential has
been applied to the dairy field both for the milk decontamination and product diversification. The
aim of this research, included in the european project “Innovative non-thermal processing
technologies to improve the quality and safety of ready-to-eat meals (HighQ RTE)”, was to evaluate
the potential of HPH to inactivate pathogenic species such as Listeria monocytogenes and Salmonella
enteritidis in raw milk and to promote the proliferation and viability of probiotic bacteria inoculated
in HPH processed milk. The data obtained were compared with those obtained using traditional heat
treatment. The results regarding the milk decontamination showed that the inactivation curves of
S. enteritidis were linear up to the 4th cycle at 100 MPa, after which their slopes diminished. Also
L. monocytogenes resulted to be sensitive to HPH. A reduction of 5 Log cfu/ml was obtained with
8 pressure pushes at 100 MPa. The use of HPH applied to milk increased the performance of the
probiotic cultures co-inoculated and extended the product shelf-life during the refrigerated storage.
The data obtained confirmed the industrial importance of this technology both for milk
decontamination and optimization of probiotic fermented milks. In addition, the effect of HPH on the
organoleptic quality of milk and milk products was evaluated in relation to sulfur and aroma
compounds detected respectively by GC-FPD and GC-MS/SPME.
2:45 p.m.
Electrodialysis With Ultrafiltration Membrane:
A New Way for Peptide Fractionation
Laurent BAZINET1*, Jean-François POULIN1, and Jean AMIOT2
1
2
Department of Food Science and Nutrition, Université Laval, Québec, CANADA
β-lactoglobulin tryptic hydrolysates contain numerous bioactive peptides and amongst others, β-lg
142-148, which has been reported to be an anti-hypertensive sequence. However, to obtain an
ingredient with higher functionality, this peptide has to be isolated. Electrodialysis with ultrafiltration
membrane (EDUF), a technique developed recently, has demonstrated very high selectivity for the
separation of acid or basic bioactive peptides. EDUF couples size exclusion capabilities of UF
membranes (membrane cut-off) with the charge selectivity (driving force = electric field) of
electrodialysis. The main goal of this work was to increase cationic peptide migration to the
permeate solution and more specifically to concentrate the β-lg 142-148 sequence by studying the
influence of three main process parameters (effective membrane surface, strength of the electrical
field and feed solution flow rate). The increase of the membrane area resulted in a 4 fold increase of
the peptide concentration. Moreover, raising the electrical field strength also resulted in increasing
considerably the peptide concentration in the permeate solution. In the best conditions, a total
migration of 29% was obtained for peptide β-lg 142-148 after only 90 minutes of processing with a
relative concentration of 30%. However, at high electrical field and membrane area, the final
migration rate was affected due to a retro-migration phenomenon linked with pH changes. It
appeared that the feed solution flow rate had no impact on the yield of the process but induced
changes in the selectivity.
19
3:45 p.m.
Microfiltration and Thermal Treatment for Extending the Shelf-Life of Milk:
Factors Affecting Product Quality and Stability
Veronika KAUFMANN*1, Verena SCHMIDT², Siegfried SCHERER², and Ulrich KULOZIK1
1,
1
²Technische Universität München, GERMANY
Chair for Food Process Engineering and Dairy Technology, ²Chair for Microbial Ecology
According to the concept of minimal processing, extended shelf-life (ESL) milk is produced by using
microfiltration (MF) in combination with a mild thermal process in a hybrid mode. Until now the
contributions for each of these processing units to operating profit were neither understood nor
quantified. Furthermore this technology is applied without sufficient knowledge about the effects of
processing conditions (e.g. filtration parameters) and up- or downstream factors (raw milk quality,
storage conditions) on product attributes and alteration. Particularly, it is not known how far these
different factors are affecting microbial survival and growth, residual enzyme activity as well as
sensory characteristics and, hence, quality and absolute shelf-life of the milk. But towards process
design and product optimization, a fundamental investigation of these interrelations is required and
therefore is the aim of this study. MF was demonstrated to remove a major part of the initial bacterial
bulk load (decimal reduction about 3.5) and thus to deliver a significant contribution to achieving a
prolonged milk shelf-life. The hybrid processing neither led to serious objectionable (chemical or
organoleptic) product alteration, but nor to a complete inactivation of all potentially shelf-life
limiting microbes (like Bacillus species) or bacterial (proteolytic and lipolytic) enzymes. It could be
shown that the shelf-life capacity of ESL milk (12 to 24 days) therefore is related to microbial as
well as enzymatical quality of the raw product and also depends on storage temperature, but much
less on processing parameters.
4:15 p.m.
Proteolysis and Lipolysis of Ultra-High Pressure Homogenized Treated Milk
During Refrigerated Storage
Julieta PEREDA*, Victoria FERRAGUT, Martín BUFFA, Buenaventura GUAMIS,
and Antonio TRUJILLO*
Centre Especial de Recerca Planta de Tecnologia dels Aliments (CERPTA), Departament de Ciència
Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, SPAIN
Ultra high-pressure homogenization (UHPH) is a new technology that is being studied as an
alternative to pasteurization. This technology is able to obtain milk with microbial and physicochemical characteristics similar to that of high-pasteurized milk. However, the effect of UHPH on
proteolysis and lipolysis has not been studied until now. Therefore, the aim of this work was
evaluating proteolytic and lipolytic changes in UHPH milks during refrigerated storage and
comparing with the effects of heat (PA; 90 ºC, 15s). Proteolysis of milk subjected to UHPH (200-300
MPa, Ti=30/40 ºC) and PA treatments and the relation of plasmin residual activity on it was studied
by capillary electrophoresis, HPLC peptide, pH-4.6-soluble nitrogen and free amino acids.
Inactivation of plasmin increased as UHPH pressure did and extensive proteolytic degradation was
observed in 200 MPa 40 ºC milk. Hydrolysis of β-casein, hydrophobic peptide and pH-4.6-SN levels
increased with the higher residual plasmin, meanwhile hydrophilic peptides were not affected.
Although, UHPH-treated samples exhibited higher casein hydrolysis compared to PA milk and there
were no significant differences in peptide and pH-4.6-SN content between 300 MPa and PA samples.
Immediately after treatments, there were no significant differences between samples in free fatty acid
(FFA) levels. During storage, an increase of FFA was observed in samples treated at 200 MPa,
however, only 200 MPa 30 ºC milk showed levels of FFA significantly higher than those of the other
UHPH and PA samples. This study shows how UHPH treatments influence milk properties,
suggesting that treatment at 300 MPa could be used as an alternative to pasteurization.
4:45 p.m.: CLOSING ADDRESS, Dr. Paul Paquin, Chairman of the Organizaing Committee
5:00 p.m. POSTER SESSION: Rooms Crémazie – Garneau, and Hall
6:30 p.m. : CLOSING DINNER at The Capitole de Québec
20
Poster presentations
Tuesday and Wednesday, May 13 - 14, 2008
Reference
Number
Title/Authors
Electroreduction of milk and effect on storage in glass jars
Laurent BAZINET*, Jérome PERICOU, and Monica ARAYA-FARIAS
1
Laval University, Quebec CANADA
[email protected]
Biodiversity of coagulase-negative staphylococci in French milk, cheeses products and
environment
Marie-Hélène DESMONTS1, Emmanuel COTON2, Monika COTON2, Emmanuel JAMET3, Sabine
LEROY4, Sylvie LORTAL*5, and Régine TALON4
2
1
Aerial CRT et ITAI, 2ADRIA Normandie, 3ITFF, 4INRA Clermont, 5INRA Rennes, FRANCE
[email protected]
Design and validation of a diagnostic microarray for microbial risk assessment in coagulase
negative staphylococci isolated from fermented dairy products
Sergine EVEN1, Sabine LEROY2, Cathy CHARLIER1, Nouri BEN ZAKOUR1,3, Jean-Paul CHACORNAC2,
Isabelle LEBERT2, Emmanuel JAMET4, Marie-Hélène DESMONTS5, Emmanuel COTON6,
Sylvie LORTAL*1, Régine TALON2, and Yves LE LOIR1
3
1
UMR1253 STLO INRA Rennes, FRANCE, 2UR454 Microbiologie, INRA Clermont Theix, FRANCE, 3LBEP,
University of Edinburgh, UK, 4ITFF, La Roche sur Foron, FRANCE, 5AERIAL, Illkirch, FRANCE, 6ADRIA
Normandie, Villers Bocage, FRANCE
[email protected]
Effect of dissolved gases and heat treatments on oxidative degradation of a dairy beverage
enriched with polyunsaturated fatty acids
4
Hélène GIROUX*, Geneviève ACTEAU, Hassan SABIK, and Michel BRITTEN
Food Research and Development Centre, Agriculture and Agri-Food Canada, Quebec, CANADA
[email protected]
Impact of ripening on probiotic-delivering capacity of semi-hard cheese: in vitro
assessment using gastro-intestinal dynamic (TIM-1) model
5
Ehab KHEADR, Nassra DABOUR, Geneviève PETIT, and
Jean-Christophe VUILLEMARD*
STELA Dairy Research Center, Institute of Nutraceuticals Functional Foods (INAF),
[email protected]
21
Poster presentations (cont’d)
Reserveratrol-β-lactoglobulin interaction studied by circular dichroism and fluorescence
Li LIANG* and Muriel SUBIRADE
6
STELA Dairy Research Center. Institute of Nutraceuticals and Functional Foods (INAF), Laval
University, Quebec CANADA
[email protected]
Lactoferrin separation by electrodialysis with ultrafiltration membrane (EDUF)
Ndiaye NAFISSATOU*1, YVES POULIOT1,,Linda SAUCIER1,2,
Lucie BEAULIEU3, and Laurent BAZINET1
7
1
STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF), Laval
University, Quebec, 2Départment of animal sciences, Laval University, Quebec, 3Department of
biology, chemistry and geography, Université du Quebec in Rimouski, CANADA
[email protected]
Study of a soluble complex of β-lactoglobulin and fucoidan,
a bioactive polysaccharide from brown seaweed
Laurie-Eve RIOUX* and Sylvie L. TURGEON
8
University, Quebec CANADA
[email protected]
Lactococcus lactis affects several staphylococcus aureus
virulence gene expression during mixed cultures
Sergine EVEN1, Cathy CHARLIER1, Marina CRETENET1, Sylvie LORTAL*1, Pascal LOUBIERE2,
Muriel COCAIGN-BOUSQUET2, Sébastien NOUAILLE2, and Yves LE LOIR1
9
1
UMR1253 STLO-INRA Rennes, FRANCE, 2LISBP, UMR CNRS 4, UMR INRA 792, INSA,
Toulouse, FRANCE
[email protected]
Effect of milk fermentation on global gene expression in human blood cells
Mary Francina SAGAYA1,2, Guy VERGÈRES1, Michel BELLIS3,
Hans-Peter BACHMAN*1, and Richard F. HURRELL2
10
1
Agroscope Liebefeld-Posieux (ALP), Bern, SWITZERLAND 2Laboratory for Human Nutrition, Institute
of Food Science and Nutrition, Swiss Federal Institute of Technology Zurich (ETHZ), Zurich,
SWITZERLAND, 3Centre de Recherche de Biochimie macromoléculaire (CRBM), Montpellier, FRANCE
[email protected]
Production and quality of cheddar cheese made from microfiltered
or CO2 acidified milk stored during 9 days
Sophie TURCOT*1, Daniel ST-GELAIS1, Gaétan BÉLANGER1, Denis ROY2, and Gisèle LAPOINTE2
11
1
Food Research and Development Centre, Agriculture and Agri-Food Canada, Quebec, CANADA,
2
[email protected]
22
Study of interactions between exopolysaccharides produced by strain lactobacillus
rhamnosus RW-9595M and milk proteins
Véronica PLESCA* and Sylvie TURGEON
12
STELA Dairy Research Center, Institute of Nutraceuticals Foods (INAF),
[email protected]
Stabilization of whey protein isolate-pectin complexes against pH adjustment
to 7.0 and their use in yoghurts
Marie-Claude GENTES*1, Sylvie TURGEON1, and Daniel ST-GELAIS2
13
1
STELA Dairy Research Center. Institute of Nutraceuticals and Functional Foods (INAF), Laval
University, Quebec CANADA, 2Food Research and Development Centre, Agriculture and Agri-Food
Canada, Quebec, CANADA
[email protected]
Oxidative stability of lipids in electro-reduced milk
Sanaz HARATIFAR*1, Laurent BAZINET1,
Michel BRITTEN2, and Paul ANGERS1
14
1
Dairy Research Center (STELA) and Institute of Nutraceuticals Foods (INAF), Laval University,
Quebec, 2Food Research and Development Centre, Agriculture and Agri-Food Canada, Quebec,
CANADA
[email protected]
Large-scale isolation of caprine and bovine β-casein.
Sophie, LAMOTHE*, Gilles ROBITAILLE, Daniel ST-GELAIS, and Michel BRITTEN
15
Food Research and Development Centre, Agriculture and Agri-Food Canada,
Saint-Hyacinthe, Quebec, CANADA
[email protected]
Calcium limits gut absorption of long chain fatty acids
during ingestion of dairy matrixes
Christelle LOPEZ1, Frédéric GAUCHERON*1, Valérie BRIARD-BION1,
Denis LAIRON2, and Jacques MOUROT3
16
1
UMR Science et Technologie du Lait et de l’France (STLO) INRA-Agrocampus, Rennes, France, 2UMR
Nutrition Humaine et Lipides INSERM 476 – INRA 1260, Faculté de Médecine de la Timone, Marseille,
France, 3UMR Systèmes d’Elevage, Nutrition Animale et Humaine (SENAH)
INRA-Agrocampus, Saint-Gilles, FRANCE
[email protected]
23
The comparative study of monolaurin treatments , and monolaurin with EDTA treatments to
control Escherichia coli post-processing contamination on Laur
(Laurec), a traditional Iranian whey cheese, stored at 4 ºC in sterile packages
Jaafarpour JAVAD1, Feiz allah beigi HOSSEIN1, Ehsani ALI2,
and Razavi ROHANI Seyed MEHDI2
17
1
Faculty of veterinary medecine, Urmia University, 2Department of food hygiene, Faculty of veterinary
medecine, Urmia University’ IRAN
[email protected]
Rheology of microgel particles made of whey protein isolate/κappa-carrageenan:
effect of shear on the microparticle size
18
Samy GAALOUL*1, Sylvie L. TURGEON1, and Milena CORREDIG2
1
STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods, Laval, University,
Quebec, CANADA, 2Department of Food Science, University of Guelph, Guelph, Ontario, CANADA
[email protected]
Analysis by real-time PCR of expression of the beta-galactosidase genes of Bifidobacterium
longum strains in the presence of various sugars during the exponential phase of growth
19
Zahira CHOUCHANE*, Ismaïl FLISS, and Denis ROY
University, Quebec, CANADA
[email protected]
Formation of structure during rennet-induced gelation of milk
containing high methoxyl pectin
20
Alexandra ACERO LOPEZ*, Milena CORREDIG, and Marcela ALEXANDER
Department of Food Science, University of Guelph, Guelph, Ontario, CANADA
[email protected]
Study of Escerichia coli infections in mammary glands of buffalo and the antibacterial drug
resistance of the isolates in Urmia Iran
21
Malahat AHMADI
Urmia University, Faculty of veterinary medicine
Department of Microbiology, Urmia, IRAN
[email protected]
24
Effect of concentration by ultrafiltration on the rennet-induced gelation of
caseins studied in situ by diffusing wave spectroscopy
Christina COOPER*, Marcela ALEXANDER, and Milena CORREDIG
22
[email protected]
Microencapsulation of probiotics by means of
enzymatically induced cross linking of dairy proteins
Thomas HEIDEBACH* and Ulrich KULOZIK
23
Technische Universität München, Chair for Food Process Engineering and Dairy Technology,
Freising, GERMANY
[email protected]
Kinetics of the lactosylation of β-lactoglobulin in a dry system
Marianne KAABER THOMSEN*, Karsten OLSEN, Jeanette OTTE,
and Leif H. SKIBSTED
24
Department of Food Science, Faculty of Life Science, University of Copenhagen, Rolighedsvej
Frederiksberg, DENMARK
[email protected]
Modeling of probiotic stability, post acidification and precipitation of a probiotic lactic
beverage produced by different combinations of milk base, starter culture, incubation
temperature, dilution and salt percentage during cold storage
25
Parinaz TAHERI1*, Mohammad REZA EHSANI2, Kianoosh KHOSRAVI DARANI3,
and Seyed HADI RAZAVI2
1
Azad University, Research and Science Branch, Tehran, IRAN, 2Department of Food Science and
Technology, Faculty of Agriculture, Tehran University, IRAN, 3Department of Food Technology
Research, National Nutrition of Food Technology Institute, Shahid Beheshti University of Medical
Science, Tehran, IRAN
[email protected]
Effects of pasteurization and ageing time on structural parameters of whipped dairy
emulsions enrichment by unsaturated fatty acids
Ali BAZMI1* and Perla RELKIN2
26
1
Food Science and Technology Group, Faculty of Agriculture, University of Tabriz, Tabriz, IRAN,
2
Laboratoire de Biophysique des Matériaux Alimentaires,
École Nationale Supérieure des Industries Alimentaires, Massy, FRANCE
[email protected]
25
Raw milk dispensers in Italy
Roberta LODI, Franco SANGIORGI*,
Milena BRASCA, and Stefano ZANDALINI
27
National Research Council-Institute of Sciences of Food Production (CNR-ISPA),
Istituto di Ingegneria Agraria dell’Università degli Studi di Milano; Milano ITALY
[email protected]
Farm sale of raw milk: old flavours and nutraceutic properties
Milena BRASCA, Roberta LODI*, Tiziana SILVETTI, and Laura VANONI
28
National Research Council-Institute of Sciences of Food Production (CNR-ISPA) Milano ITALY
[email protected]
Effect of experimental staphylococcus aureus mastitis on composition of goat milk
Nancy MUNGATANA
29
University of Egerton, KENYA
[email protected]
Human blood neutrophils primed by a bovine whey protein extract increase their
specialized functions of innate defense
30
Daniel RUSU1*, Réjean DROUIN2, Sylvie GAUTHIER3,
Yves POULIOT3, and Patrice E. POUBELLE1
1
Centre de recherche en rhumatologie et immunologie (CRCHUL), 2Advitech inc., Québec, 3STELA
Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF), Université Laval,
CANADA
[email protected]
Structure formation during acidification of milk: Study based on
scanning electron microscopy (SEM)
31
Ivo PISKA* and Douglas G. DALGLEISH
[email protected]
Correlation between non-enzymatic browning reactions and the loss of vitality
of probiotic bacteria in freeze-dried dairy cultures
32
Charlotte U. CARLSEN*, Lone KURTMANN,
and Leif H. SKIBSTED
Food Chemistry, Department of Food Science, Faculty of Life Science,
University of Copenhagen, Frederiksberg, DENMARK
[email protected]
26
_____________________________________________________________________
Viability of bifidobacteria strains in yogurt and simulated gastrointestinal transit
Terri D. BOYLSTON*, Karen S. KERR, and
Aubrey F. MENDONCA
33
Iowa State University, Dept. Food Science & Human Nutrition, Ames, Iowa, USA
[email protected]
Dynamic in vitro gastrointestinal digestion (TIM-1)
of a growth factors-enriched whey product: hydrolysis profile and effect
on intracellular glutathione of digested fractions
Samira NABIL*1, Sylvie F. GAUTHIER1,
Réjean DROUIN2, and Patrice POUBELLE3
34
1
STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF),
Laval University, Quebec, CANADA 2Advitech inc., Quebec, CANADA,
3
Research center in rhumatology and immunology (CRCHUL), Quebec, CANADA
[email protected]
Production of galacto-oligosaccharides and hetero-oligosaccharides with disrupted
bacterial cells
Vivian LEE*, Clarissa SCHWAB, and Michael GÄNZLE
35
Department of Agricultural, Food, and Nutritional Sciences, University of Alberta, CANADA
[email protected]
Potentialities of high pressure homogenization for the production of bio-yoghurts
36
Francesca PATRIGNANI1, Rosalba LANCIOTTI1, Maurice NDAGIJIMANA1, Wilhelm H. HOLZAPFEL2,
and M. E. GUERZONI1.
1
Alma Mater Studiorum - University of Bologna, Department of Food Science, Bologna, ITALY,
2
Institute of Hygiene and Toxicology, Federal Research Centre for Nutrition, GERMANY
[email protected]
Bio-K+ International: Clinical research;
efficacy and safety of Bio-K+ CL1285®
Marcia T. RUIZ*1, François MARTIN2, and Serge CARRIERE2
37
1
Bio-K+ International, Montreal, Quebec, CANADA, 2Université de Montréal, CANADA
[email protected]
Sodium caseinate affects the aggregation of rennet-altered casein micelles
38
Zafir GAYGADZHIEV*, Marcela ALEXANDER,
Arthur HILL, and Milena CORREDIG
[email protected]
27
Séparation of TGF-β2 from a whey protein isolate by crossflow microfiltration
in the presence of a ligand
Wassef BEN OUNIS*1, Sylvie F. GAUTHIER1, Sylvie L. TURGEON1,
Olivier MORONI2, and Yves POULIOT1
39
1
STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval
University, Quebec, CANADA, 2Advitech inc., Quebec, CANADA
[email protected]
Effect of processing on triacylglycerol composition in milk fractions
Samia MEZOUARI*1, Michel BRITTEN2, Paul ANGERS1, and Yves POULIOT1
40
1
University, Quebec, CANADA, 2Food Research and Development Center, Agriculture and Agri-Food
Canada, Quebec, CANADA
[email protected]
Serum cholesterol level in mice: effects of probiotics and milk lipid extracts
41
Cuibai FAN*, Anne-Marie DAVILA, Michel DUBARRY,
Agnes BAGLIERI-MARSSET, and Daniel TOME
UMR914 Nutrition Physiology and Ingestive Behavior, INRA, AgroParisTech,
CRNH- Paris, FRANCE
[email protected]
Effect of pasteurization on the interactions between casein micelles
and milk fat globule membranes in cream and buttermilk
42
Sophie IZMIROGLU*1, Michel BRITTEN2,
Laurent BAZINET1, and Yves POULIOT1
1
University, Quebec, CANADA, 2Food Research and Development Centre, Agriculture and Agri-Food
Canada, St-Hyacinthe, Quebec, CANADA
[email protected]
Protein composition changes in bovine milk fat globule membrane
isolated from buttermilk caused by industrial pasteurization
Jessika BÉDARD-ST-AMANT*1, Yves POULIOT1,
Sylvie GAUTHIER1, Dominique MICHAUD2, and Michel BRITTEN3
43
1
University, Quebec, CANADA, 2Department of Phytology and Institute of Nutraceuticals and Functional
Foods (INAF), Laval University, Quebec, CANADA, 3Food Research and Development Centre,
Agriculture and Agri-Food Canada,
Saint-Hyacinthe, Quebec, CANADA
[email protected]
28
Antibacterial activity of peptide fractions isolated
from a tryptic hydrolysate of whey proteins
44
Émilie TURGEON*, Sylvie GAUTHIER, Ismail FLISS, and Julie JEAN
University, Quebec, CANADA
[email protected]
Fractionation of β-lactoglobulin peptide mixture by means of
nanofiltration in the presence of ligands
45
Bertrand P. CHAY PAK TING, Sylvie F. GAUTHIER, and Yves POULIOT
STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University,
Quebec, CANADA
[email protected]
A new technological approach for the bovine colostrum fractionation
David P. LACHKAR*1, Éric LAMIOT2, Sylvie L. TURGEON1, Sylvie F. GAUTHIER1, and Yves POULIOT1
46
1
University, Québec, CANADA, 2Advitech Inc., Quebec, CANADA
[email protected]
Digestion of conjugated linoleic acids (CLA) from different sources
in a dynamic in vitro gastrointestinal model
47
Rachel. GERVAIS*1, Edward R. FARNWORTH1,2, Ismaïl FLISS1, Ehab E. KHEADR1,
M.R. VAN CALSTEREN2, Claude CHAMPAGNE1,2, and P.Yvan CHOUINARD1
1
University, Quebec, CANADA, 2Agriculture and Agri-food Canada, St-Hyacinthe, Quebec, CANADA
[email protected]
Emulsifiers for granulated ghee
Ravindra KUMAR1 and Niels Erik LARSEN2
48
1
2
Danisco (India) Pvt. Ltd, Gurgaon, INDIA,
Danisco A/S, Edwin Rahrs, Brabrand, DENMARK
[email protected]
Characterization of acid-induced gels of mixtures of β-lactoglobulin and α-lactalbumin
49
Ladan RABIEY*, and Michel BRITTEN
Agriculture and Agri-Food Canada, Saint-Hyacinthe, Quebec, CANADA
[email protected]
29
Evaluation of the impact of microfiltration, acidification with carbon dioxide and
prolongation of the storage period of milk on the diversity and dynamics
of the bacterial community during ripening of Cheddar cheese
Sadjia RACHEK*1, Daniel ST-GELAIS2, Gisèle LAPOINTE1, Steve LABRIE1, and Denis ROY1
50
1
University, Quebec, CANADA, 2Agriculture and Agri-Food Canada, St-Hyacinthe, Quebec, CANADA
[email protected]
Transcriptome profiling of Lactococcus lactis subsp. cremoris under conditions
simulating Cheddar cheese manufacture.
Amel TAÏBI*1, Nassra DABOUR1, Maryse LAMOUREUX2, Denis ROY1, and
Gisèle LAPOINTE1
51
1
University, Quebec, CANADA, 2Agropur, inc., Granby, Quebec, CANADA
[email protected]
Impact of digestive stresses on tolerance and metabolic activity of
bacteriocin-producing lactic acid bacteria and bifidobacteria
Jedidi HAJER*, Ehab E. KHEADR, and Ismail FLISS
52
STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF),
Laval University, Quebec, CANADA
[email protected]
Combined effects of bacteriocins and gastrointestinal stress conditions on the inhibition of
listeria mononcytogenes
53
Helen ENGEL1, Christophe LACROIX1, Annina ZIHLER1, Ehab KHEADR2, and
Ismaïl Fliss*2
1
Institute of Food Science and Nutrition, Swiss Federal Institute of Technology, Zentrum, CH-8092
Zürich, SWITZERLAND, 2STELA Dairy research Center, Institute of nutraceuticals and Functional
Foods (INAF), Laval University, Quebec, CANADA
[email protected]
Impact of Lactobacillus acidophilus NCFM cell surface proteins on its binding
to milk fat globule membrane in buttermilk
54
Guillaume BRISSON* and Rafael JIMENEZ-FLORES;
Dairy Product Technology Center, California Polytechnic State University,
San Luis Obispo, CA 93407, USA
[email protected]
30
A new central source for bacteriocins characterization
Riadh HAMMAMI1, Abdelmajid ZOUHIR1, Jeannette BEN HAMIDA1, and Ismail FLISS2§
55
1
Unité de Protéomie Fonctionnelle & Biopréservation Alimentaire, Institut Supérieur des Sciences
Biologiques Appliquées de Tunis, Université El Manar, Tunisie, 2STELA Dairy Research Center, Institute
of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA
§
[email protected]
Use of scientific database maker for the characterization of protein sequences and design of
specialized biological databases
Riadh HAMMAMI 1, Abdelmajid Zouhir1, Jeannette Ben Hamida1 and Ismail Fliss2§
1
Unité de Protéomie Fonctionnelle & Biopréservation Alimentaire, Institut Supérieur des Sciences
Biologiques Appliquées de Tunis, Université El Manar, TUNISIE, 2STELA Dairy Research Center,
Institute of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA
§
[email protected]
mardi 20 mai 2008
31
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Program - INAF - Université Laval

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