Prevalence of some deteriorating microorganisms in raw milk and some locally made cheese

Food deterioration has become a very important issue as excessive amounts of food are lost due to microbial spoilage. The work aimed to assess the microbiological quality of raw milk and soft locally made cheeses in Assiut city, Egypt. A total of one hundred and fifty random samples of raw bovine milk (90 samples) and locally made cheese including Kareish and Domiati cheese (30 samples each) were collected randomly from different localities in Assiut city, Egypt. These samples were examined for microbiological evaluation. The investigation revealed that the average APC were 1.9×106, 2.6×106, 6.2×106, 7.5×105 and 1.8×105 cfu/ml or /g for dairy farm milk, dairy shops, street vendor raw milk, Kareish cheese and Domiati cheese, respectively and the average Psychrotrophic count was 8.3×105, 1.0×106, 1.5×106, 2.5×105 and 9.0×104 cfu/ml or /g while the average Proteolytic count was 1.6×105, 2.1×105, 3.7×105, 5.3×104 and 2.0×104 cfu/ml or /g. Additionally, the average Lipolytic count was 2.5×105, 3.9×105, 6.5×105, 9.8×104 and 2.8×104 cfu/ml or /g for the above-mentioned samples respectively. On the other hand, the Lactobacillus counts were 5.5×104, 8.8×104, 1.4×105, 1.9×104 and 5.2×103 cfu/ml or /g, respectively. The average count of total yeast and molds were 9.5×102, 2.5×103, 7.5×103, 7.5×102 and 6.2×102 cfu/ml or /g, respectively. In conclusion, the presence of these organisms indicted that the examined samples were of low quality which reflect unhygienic measures during milking, processing, storage, and distribution chain.