MEAT-LIVER GLUCOSE AGAR

MEAT-LIVER GLUCOSE AGAR
INTENDED USE
Meat-liver Glucose Agar is used to enumerate spores of sulfite-reducing clostridia in water (according
to French standard NF T 90-415), in dairy and in other food products.
PRINCIPLES
- Meat-liver peptone assures the growth of most microorganisms, particularly that of anaerobic
bacteria.
- Glucose is the energy source for growth.
- Starch favors spore germination.
- Anaerobic bacteria reduce sulfite to sulfide, which in presence of ferric ions causes the blackening
of the colonies due to the formation of iron sulfide.
PREPARATION
-
Suspend 48.0 g of dehydrated medium (BK157) in 1 liter of distilled or deionized water.
Slowly bring to boiling, stirring with constant agitation until complete dissolution.
Dispense 20 mL in appropriate tubes.
Sterilize in an autoclave at 121°C for 15 minutes.
NOTE :
Incomplete agar melting during preparation will invariably lead to significant inconsistency in the gel
strength of the solidified agar, after sterilization and cooling.
INSTRUCTIONS FOR USE
- Cool and maintain the medium at 44-47°C.
- Heat the product to analyze in order to destroy vegetative cells and activate spores.
- Transfer the medium to a tube containing 5 mL of inoculum or its serial tenfold dilutions, carefully
avoiding the incorporation of air.
- Homogenize by inverting the tubes.
- Cool in an ice-water bath.
- Incubate at 37°C for 24 to 48 hours.
RESULTS
Count colonies surrounded by a black halo.
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Biokar Diagnostics – Rue des Quarante Mines – ZAC de Ther – Allonne – B.P. 10245 – F60002 Beauvais Cedex – France
Tél : + 33 (0)3 44 14 33 33 – Fax : + 33 (0)3 44 14 33 34 – www.biokar-diagnostics.com
TYPICAL COMPOSITION
(can be adjusted to obtain optimal performance)
For 1 liter of medium :
- Meat-liver peptone .........................................................................30.0 g
- Glucose ............................................................................................2.0 g
- Soluble starch ..................................................................................2.0 g
- Sodium sulfite ..................................................................................2.5 g
- Ferric ammonium citrate ..................................................................0.5 g
- Bacteriological agar .......................................................................11.0 g
pH of the ready-to-use medium at 25°C : 7.6 ± 0.2.
QUALITY CONTROL
- Dehydrated medium : off-white powder, free-flowing and homogeneous.
- Prepared medium : amber agar.
- Typical culture response after 18-24 hours incubation at 37°C :
Microorganisms
Growth
(Productivity ratio R2 and PR)
Characteristics
Clostridium perfringens ATCC® 13124
Clostridium perfringens
NCTC 8238
(2)
Clostridium bifermentans ATCC 19299
(2)
Clostridium sporogenes
ATCC 11437
66% < R2 < 150%
PR ≥ 70%
PR ≥ 70%
PR ≥ 70%
black colonies
black colonies
black colonies
black colonies
(1)
(2)
(1)
(2)
Anaerobic incubation, in Petri dishes, and Productivity ratio R2 acc. to NF T 90-415, NF T 90-461
Productivity ratio PR acc. to XP CEN ISO/TS 11133-2
STORAGE / SHELF LIFE
Dehydrated medium (BK157) : 2-30°C.
- The expiration dates are indicated on the labels.
Prepared medium (benchmark value*) : 6 months at 2-8°C.
- Regenerate at 100°C for 20 minutes before inoculation.
- Do not repeat the operation more than once.
Code
PACKAGING
Dehydrated complete medium :
- 500 g bottle
BK157HA
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Biokar Diagnostics – Rue des Quarante Mines – ZAC de Ther – Allonne – B.P. 10245 – F60002 Beauvais Cedex – France
Tél : + 33 (0)3 44 14 33 33 – Fax : + 33 (0)3 44 14 33 34 – www.biokar-diagnostics.com
BIBLIOGRAPHY
NF T 90-415. Octobre 1985. Essais des eaux. Recherche et dénombrement des spores de bactéries anaérobies sulfitoréductrices et de Clostridium sulfito-réducteurs. Méthode générale par incorporation en gélose en tubes profonds.
XP CEN ISO/TS 11133-2 (V 08-104-2). Janvier 2004. Microbiologie des aliments. Guide pour la préparation et la production
des milieux de culture. Partie 2 : Guide général pour les essais de performance des milieux de culture.
NF T 90-461. Juillet 2001 et NF T 90-461/A1. Juin 2005. Qualité de l’eau. Microbiologie. Contrôle qualité des milieux de
culture.
*Benchmark value refers to the expected shelf life when prepared under standard laboratory conditions following manufacturer’s instructions. It is provided as a
guide only and no warranty, implied or otherwise is associated with this information.
The information provided on the package take precedence over the formulations or instructions described in this document.
The information and specifications contained in this technical data sheet date from 2009-02-17.
They are susceptible to modification at any time, without warning.
Code document : BK092 & 157/A/2001-07 : 6.
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Biokar Diagnostics – Rue des Quarante Mines – ZAC de Ther – Allonne – B.P. 10245 – F60002 Beauvais Cedex – France
Tél : + 33 (0)3 44 14 33 33 – Fax : + 33 (0)3 44 14 33 34 – www.biokar-diagnostics.com