BRYANT AND BURKEY AGAR

Bryant and Burkey Agar is used to enumerate the spores of gasogenic clostridia that are responsible for swelling of cheese in dairy industry. In normal conditions of use, the medium allows the growth of other microorganisms also which are not directly related to cheese alteration, e.g. Clostridium sporogenes or Clostridium butyricum. Germination and growth of butyric acid bacteria (BAB) causes severe defects in cheese with silage being the main source of BAB spores in cheese milk. Clostridia spores are heat resistant and therefore can contaminate cheese brines. The gas produced by the growth of clostridia swells the cheese and is responsible for defect known as butyric swelling, resulting in bad taste. The main species causing this butyric swelling defect is Clostridium tyrobutyrium.
Bryant and Burkey Agar is the modification of Bryant and Burkey Medium with addition of little amount of agar that makes the medium thicker to be used in greater volumes. Addition of sodium thioglycollate maintains anaerobic conditions and also the amount of lactate is reduced so that the density of the medium will be retained easily for the production of gas bubbles.

for detection and enumeration of spores of lactate fermenting Clostridiffm in dairy products