Bacteriology Of Processed Cheese With Special Reference To The Expiry Date

Abstract

A total of eighty-eight samples of different kinds of cheese with different validity dates, were subjected to bacteriological examinations. All isolates were Gram-positive except one which was Gram-negative. “Eighty seven organisms were isolated out of these samples including Bacillus species 48.27% (B. thuringiensis, B. mycoides, B. cereus, B. pantothenticus, B. lentus and B. badius), Staphylococcus species 22.98% (S. capitis subsp. ureolyticus, S. chromogenes, S. carnodus, S. hyicus, and S. warneri), Micrococcus species 5.74% (M. sedentarious, M. kristinae, M. nishinomiyaesis and, M. luteus), Enterococcus faecium (11.49%) Pediococcus species (2.29%), Leuconostoc species (3.44%), Corynebacterium species (2.29%), Lactobacillus casei (1.14%), Listeria seeligeri (1.14%) and Actinobacillus lignieresii (1.14), which was the only Gram-negative among the isolates. Viable bacterial count results showed that, the number of bacteria in the different cheese samples ranged between 104 – 3.1 ×107. Mozzarella cheese was examined bacteriollogically during manufacturing process, beginning with milk, from which Bacillus cereus was isolated, secondly cheese curd from which Escherichia coli and Staphylococcus aureus were isolated and finally processed cheese from which S. chromogenes and Enterococcus faecium were isolated.