[Development and resistance of staphylococci in Bulgaricus milk]

Studied was the dynamics of development of 9 strains of staphilococci isolated from humans and animals, kept in heat-treated milk, and their resistance in Bulgarian sour milk. It was established that the pathogenic Staph. aureus and Staph. epidermidis develop will in fresh milk kept up to 7 days at 2--6degreesC and 18--22degreesC. In the production of Bulgarian sour milk Staph, aureus was shown to be viable, remaining active for seven days at 2 to 6degreesC. At room temperature (18--22degreesC) the survival rate has been dependent on the dynamics of accumulating metabolite products in connection with the development of Lactobac. bulgaricum and Streptococcus thermophilus. When the total acidity value reaches 160degreesT the pathogenic staphylococci are destroyed. Staphylococcus epidermidis finds no favourable medium to develop in Bulgarian sour milk, and it perishes when the total acidity is 120degreesT and pH -- 3.