PROTEOLYTIC PSYCHROTROPHIC BACTERIA IN SOME DAIRY-PRODUCTS IN EGYPT

One hundred samples of dairy products, i.e. UHT milk, sour cream, Ras, Cheddar and Domiati cheeses, available in Cairo and Giza governorates were collected and examined for standard plate count, psychrotrophic bacterial count and proteolytic psychrotrophic bacterial count. Proteolytic psychrotrophic bacteria isolates (213 cultures) were identified to the different species. The highest numbers of standard plate count, psychrotrophic bacterial count and proteolytic psychrotrophic bacterial count, 32 x 10(7), 62 x 10(6) and 71 x 10(5) cfu/g, respectively. were found in the sour cream samples. The Gram-negative isolates (61 cultures) were identified to the different species among the genera Pseudomonas, Alcaligenes, Flavobacterium, Citrobacter, Enterobacter and Proteus. The Gram-positive isolates (152 cultures) belonged to Streptococcus, Staphylococcus, Microbacterium and Brevibacterium.