STARCH MILK AGAR

Description

The milk secreted in an uninfected cows udder is sterile. Contamination of this milk can occur during milking, cooling and storage. Milk is an excellent medium for bacteria, yeast and moulds. Their rapid growth can cause marked deterioration, spoiling the milk for liquid consumption or manufacture into dairy products. Human infection can occur by consumption of such contaminated milk or milk products. Spore-forming bacteria can survive food-processing treatments. In the dairy industry, Bacillus and Clostridium species determine the shelf-life of a variety of heat-treated milk products, mainly if the level of post-process contamination is low. Starch Milk Agar is used for the detection of spores in heated milk and milk products. It helps in the demonstration of starch hydrolysis and proteolytic activity of spore producing organisms in milk and milk products. Proteolytic bacteria will be surrounded by a clear zone, due to the conversion of casein into soluble nitrogenous compounds.