Microbial safety criteria and quality of traditional Egyptian Karish cheese

Some traditional fermented dairy products like Egyptian Karish cheese and traditional fermented milk (Laban Zeer) are manufactured in farmhouses following traditional techniques using raw milk without heat treatment or addition of selected starter cultures, these products are generally designed as “artisanal”. The representative Karish samples were analyzed for their content of total microbial, Enterobacteriaceae, yeast, molds, Staphylococci coagulase positive, Salmonella spp., Listeria spp., in addition to detection of Bacillus cereus, Listeria monocytogenes, Clostridium perfringens and Campylobacter spp. using classical methods. The physico-chemical properties of collected samples showed that the average of protein, fat, moisture and acidity were in accepted range with that reported in literatures and Egyptian standard. Some lactic acid bacteria (Lactococcus lactis supsp. lactis, Lactobacillus delbrueckii subsp. lactis and Enterococcus feacium) were isolated and identified from fresh karish cheese using classical methods followed by rep-PCR. Lactococcus garvieae was detected in fresh samples using TTGE but could not be detected using classical methods. The results of microbiological analysis showed the presence of high numbers of Enterobacteriaceae that ranged from log10 2.6 cfu/g to log10 3.5 cfu/g, Bacillus ssp. ranged from log10 4.2 cfu/g to log10 5.6 cfu/g, Staphylococci counts are ranged from log10 1.8 cfu/g to log10 2.7 cfu/g, faecal enterococci count ranged from log10 3.5 cfu/g to log10 5.8 cfu/g. Yeasts and molds count ranged from log10 2.7 cfu/g to log10 3.5 cfu/g. B. cereus, L. monocytogenes, C. perfringens, Shigella, Salmonella, Escherichia coli β-glucuronidase positive and Campylobacter spp. were not detected in all the examined samples. The count of undesirable microorganisms indicated the poor hygienic practice of traditional Karish cheese production; starting with using poor quality of raw milk and processing under uncontrolled environments. This would require using clean raw milk, controlled manufacturing steps and selection of the appropriate starter culture for the fermentation.