BRYANT BURKEY BROTH WITH RESAZURIN AND &

General description

Bryant Burkey Broth with Resazurine and Lactate is used to enumerate the lactic acid fermenting Clostridium spores in silage, milk, and dairy products. During the milking process, low numbers of butyric acid fermenting bacteria (BAB) originating from silage are introduced into the raw milk. When the contaminated milk is used for cheese production, cheese brines become contaminated with heat-resistant Clostridia spores. During the ripening of salt-brined, semi-, and hard cheeses (for example, Gouda, Edammer, Emmentaler, Gruyere, and Parmesan), "late blowing" gas forming Clostridia ferment lactate into butyric acid, acetic acid, and gas (CO₂ and H₂). The gas swells the cheese and is responsible for a defect termed "late blowing" or butyric swelling. The blown-up cheese has a foul taste. The main species causing this butyric swelling defect is C. tyrobutyricum. Other Clostridia belonging to the butyric acid fermenting bacteria (BAB) are C. butyricum or C. sporogenes. The causative Clostridium spp. are anaerobic Gram-positive microorganisms forming heat-resistant endospores, which survive pasteurization but not UHT or sterilization of milk.

Application

Bryant Burkey Broth (with Resazurine and Lactate) is suitable for the selective enrichment of lactate fermenting Clostridium spp. (C. tryobutyricum) which are responsible for "late blowing" in brine-salted semi-hard cheese.

Features and Benefits

• NutriSelect^® prime range offers powdered high-quality and cost-efficient culture media, all made from selected raw materials
• Regulatory F&B and pharma industry standards
• QC with Growth Promotion Test acc. To regulatory standards (ISO, FDA-BAM, EP, and USP; and QC under ISO 17025 accreditation)

Principle

The method uses the MPN (Most Probable Number) procedure to detect the presence of spores, but not vegetative cells, since samples are heated to inactivate vegetative cells. Since C. tyrobutyricum spores are more heat sensitive than many other Clostridium spp., higher temperatures or longer heat treatments should be avoided. Resazurin is a redox indicator and monitors the oxygen level. The nutrient composition of the basal medium, particularly the high quality of the peptones enables rapid growth of lactate fermenting Clostridium spp. Lactate acts as the carbon source to allow selective growth of lactate-fermenting spore formers and is the substrate for the gas production of Clostridium spp. Sodium acetate facilitates lactate fermentation by C. tyrobutyricum. Sodium acetate also promotes spore germination, which is activated by the heat treatment of the sample. Raised paraffin plug indicates strong gas production.

Analysis Note

Appearance (clearness)clear to almost clearAppearance (colour)yellowishAppearance (Oxidation area)pinkpH-value (25 °C)5.8 - 6.0Growth (Clostridium tyrobutyricum DSM 663)good to very goodGrowth (Clostridium perfringens ATCC 10543)good to very goodGrowth (Escherichia coli ATCC 25922 (WDCM 00013))good to very goodGrowth (Staphylococcus aureus ATCC 25923 (WDCM 00034))good to very goodGrowth (Pseudomonas aeruginosa ATCC 27853 (WDCM 00025))noneGas (Clostridium tyrobutyricum DSM 663)+Gas (Clostridium perfringens ATCC 10543)+Gas (Escherichia coli ATCC 25922 (WDCM 00013))fair/noneGas (Staphylococcus aureus ATCC 25923 (WDCM 00034))-Gas (Pseudomonas aeruginosa ATCC 27853 (WDCM 00025))-Incubation: up to 3 days; 35 °C; anaerobic.

Footnote

We offer two media types: the superior granulated GranuCult^® and the cost-efficient powdered NutriSelect^® culture media, depending on your needs.
The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

Legal Information

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany

NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany