ASSESSMENT OF MICROBIAL QUALITY AND CHEMICAL CON- TAMINATION OF SOME MILK AND MILK PRODUCTS
Abstract
Food contamination poses a significant threat to public health, potentially causing illnesses due to the presence of infectious organisms like fungi, bacteria, viruses, parasites, or their toxins. Notable bacteria contributing to contamination include Salmonella spp., Escherichia coli, and Staphylococcus aureus, each capable of causing various infections. Additionally, chemical contaminants like Aflatoxin M1 further compound the risks, being known carcinogens. This study aimed to evaluate the microbial quality and chemical contamination of selected milk and milk products. Twenty-five samples were weighed and subjected to enrichment media, followed by culturing on specific selective media for identification of bacteria such as E. coli, Staphylococcus. aureus, coliforms, and Salmonella spp., further confirmed through confirmatory tests. Shiga-toxin producing E. coli (STEC) was identified using Real-time PCR, while PCR and Gel Electrophoresis were utilized to determine the pathogenic group of E. coli. Furthermore, liquid chromatography (LC) analysis was conducted to quantify Aflatoxin M1 levels in the samples. Analysis revealed that 56% of tested samples were positive for E. coli, while 76% contained suspected coliform colonies, with 72% confirmed. Additionally, 12% of samples harbored STEC, while none contained Salmonella or S. aureus. Alarmingly, 88% of samples exceeded Egyptian regulations for Aflatoxin M1 (> 0 ug/Kg), with 52% surpassing EU regulations (> 0.05 ug/Kg). These findings underscore significant contamination of milk and dairy products by various bacteria and the presence of excessive Aflatoxin M1 levels, highlighting the urgent need for regulatory measures and quality control in the food industry.
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