Microbial profile and aflatoxin M₁ in some dairy products and cheese analogues / Abdelkareem Hamed Adam Abdellatif ; Supervised Salwa Ahmed Mohamed Aly , Mena Fouad Saad

Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Food Hygiene and Control

Dairy products have a significant value in human nutrition but may harbor risk to public health, therefore monitoring of dairy products is highly essential to safeguard consumers. This thesis aimed to investigate the possible microbiological hazards as well as Aflatoxin M1 in some dairy products. A total of 300 samples (50 each of cheese analogue; flavored yogurt; flavored drinking yogurt; kariesh cheese; white soft cheese, and Ras (Roumy) cheese) were collected from street vendors, dairy shops, and supermarkets at three various districts, El-Fayoum governorate, Egypt. The obtained results revealed that aerobic spore formers, Bacillus cereus (B. cereus), total staphylococci, total coagulase-positive staphylococci (TCPS), coliforms (MPN/g), and total yeast & mold were present in percentages of 36, 4, 30, 0, 0 and 24% in the examined cheese analogue samples ;66, 6, 58, 18, 64 & 30% in flavored yoghurt samples; 88, 8, 42, 0, 32 and 54% in flavored drinking yogurt samples; 76, 6, 100, 20, 88 and 78% in kareish cheese samples; 56, 8, 96, 20, 76 and 36% in white soft cheese samples, and 86, 6, 100, 22, 86 and 36% in the examined Ras cheese samples. Bacillus cereus isolates were confirmed and tested for enterotoxigenic genes via biochemical and molecular approaches using Polymerase Chain Reaction (PCR). The nhe gene is the most detected gene (100%) in all of the examined isolates, followed by cytK (52.6%), and ces (5.3%) genes. The hbl and bceT genes could not be detected in all of the examined isolates. Escherichia coli and salmonella failed to be detected in all of the examined samples (100.0% compliance with the Egyptian Standard Regulation)

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