Slanetz-Bartley Medium with TTC added is a very selective medium recommended for the isolation and enumeration of enterococci in water and foodstuffs by the membrane filtration technique. It is also suitable for the industrial preparation of poured plates. Burkwall and Hartman demonstrated that the addition of 0,5 ml of Tween 80 and 20 ml of a 10 % Sodium carbonate or bicarbonate solution to each liter of the medium was valuable when investigating enterococci in frozen foods. Tryptose provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Glucose is the fermentable carbohydrate providing carbon and energy. Dipotassium phosphate is a buffer. Sodium azide inhibits Gramm negative bacteria. Triphenyltetrazolium chloride is reduced to formazan by the enterococci. Bacteriological agar is the solidifying agent. The ISO standard 7899-2 recommends this medium for the enumeration of enterococci in water systems. Water is filtered through a membrane, which is then placed on the surface of a plate of Slanetz-Bartley Medium. The plate is incubated at 36Â±2 ºC for 44Â±4 hours. The membrane is examined with a magnifying lens under good light and all red or brown colonies are counted as presumptive enterococci. With a positive presumptive result, the membrane with the typical colonies is transferred to a dish with Bile Esculin Azide Agar (Cat. 1005), pre-warmed to 44°C. The plates are incubated at 44Â±0,5 ºC for 2 hours. After incubation, typical colonies (brown-black surrounding the medium) are counted as intestinal enterococci. This medium also complies with the recommendations of the British Ministry of Health Report 71, and the German DIN Regulations 10181 and 10160 for the examination of milk, meat and meat products.
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