[Microbiological studies of Mladost sour milk]

Studied were a total of 239 productional batches of Mladost sour milk to establish the occasional contamination with coliform bacteria. It was found that 97.9 per cent of the batches had coli titers of 0.1 and over 0.1, and 2.1 per cent of the batches--over 0.01. Fourteen productional experiments were carried out to ascertain the sources of contamination with coli forms, yeasts, and moulds. It was found that the productional starter used for this type of sour milk did not contain coliforms and moulds in 0.1 cm3 but in about 43 per cent of the batches it contained 20 to 470 cm3 yeasts. It was also established that both yeasts and moulds that have found their way to the product multiplied in it to a various extent, depending on the activity of the cultures and the temperature of storage. Some of the stored batches deteriorated in terms of their organoleptic indices. At 11,000 cm3 yeasts the deterioration becomes stronger following the cummulation of greater amounts of biomass.