Two hundred and fifty samples (Marketable milk, Ras cheese, Domiati cheese and ice cream), were randomly obtained from various dairy shops, supermarkets and ice cream shops in Assiut City, Egypt, during the period of November 2022 to March 2023. These samples were examined for the detection and counting of Bacillus cereus. The positive B. cereus isolates were analyzed by PCR to detect 16s rRNA gene for B. cereus, cytotoxin K (cyt K) and emetic gene (ces). Out of the 250 examined samples, 14 (5.6%) were contaminated by B. cereus. The analyzed ice cream had the highest prevalence (11.53%), followed by Ras cheese samples. The prevalence of ces gene recorded in the examined isolates was 57.14%, while cyt K gene was found in all isolates. Moreover, proteolytic and lipolytic activity investigations revealed that nearly all strains released protease enzyme (92.85%), most of which (64.28%) could produce lipase enzyme.

A frequent source of milk contamination is Bacillus cereus. The microorganism can contaminate raw milk at the time of milking since it is ubiquitous in the environment. In the current study, one hundred raw milk samples were obtained from farmers, supermarkets, street vendors and dairy shops in Egypt, collected samples were examined biochemically and by vietk 2 compact system to isolate Bacillus cereus. Prevalence values of B. cereus were 0, 20,8 and 12% respectively.  The Mean ± SE of the pH values for milk samples were 6.54 ± 0.04, 6.48 ± 0.06, 6.44 ± 0.05 and 6.53 ± 0.06 respectively, on the other hand sorch’s test for milk samples was positive in a percentage of 12, 8, 40 and, 16, respectively. Molecular characterization of hlbA and ces showed positive reaction for 30 and 20% of samples. Growth, proteolytic and lipolytic activities of Bacillus cereus was 100, 100, 20 and 40, 40, 20 at 30◦C/48 h and 7°C/10 days, respectively. Outcomes of the in vitro testing for susceptibility indicated that the highest resistance to antibiotics was against macrolides and mono, B-lactamase, whereas moderate resistance was exhibited to gentamicin. The current study's findings exhibited evidence of B. cereus isolation from raw milk has a high potential for producing food poisoning, so it is necessary to employ the techniques to lessen bacterial contamination while processing dairy products.

Because milk is rich in nutrients, it creates an environment conducive to the growth of bacteria that could be harmful to consumers. Therefore, assessing of its bacteriological quality and the resistance of these pathogens to several antibiotic groups is very important. VITEK 2 compact detected E. coli, Salmonellae spp., S. aureus and B. cereus in the examined samples while it failed to detect Listeria spp. The serological identification of E. coli showed the presence of O44: H18, O127: H6, O159, O15: H2, and O91: H21. Also, Salmonella serotypes as           S. enteritidis (25%), S. infantis (12.5%), S. kentucky (12.5%), S. montevideo (6.25%), S. shangani (12.5%), S. tsevie (12.5%). S. typhimurium (18.75%).  Furthermore, the entero-toxigenic strains of S. aureus were 31.25% of the identified strains; the percentage of entero-toxigenic strains that secrete A, A&C and D enterotoxin were 60%, 20% and (20%); respectively. Ampicillin, amoxicillin / clavulanic acid, cefpodoxime, cefovecin, ceftiofur, and trimethoprim / sulfamethoxazole were all ineffective against the isolated E. coli strains. Intermediate sensitive to cefalothin while they were sensitive to cefalexin, imipenem, amikacin, gentamicin, neomycin, enrofloxacin, marbofloxacin, pradofloxacin, doxycycycline, tetracycline, nitrofurantoin and chloramphenicol. Additionally, the isolated S. aureus exhibited resistance to tetracycline, benzylpenicillin, oxacillin, gentamycin, ciprofloxacin, levofloxacin, and moxifloxacin also; it showed intermediate resistance to rifampicin. The identified S. aureus strains were also susceptible to linezolid, nitrofurantoin, vancomycin, tigecycline, and trimethoprim / sulfamethoxazole.

One of the most common food poisoning illnesses globally is caused by Bacillus cereus, which causes emetic and diarrheal food poisoning. Forty–two (42%) out of 100 samples from raw milk, powdered milk, ice cream, and pasteurized milk were positive for B. cereus, with a high prevalence in raw milk at 64%. Three virulence genes (nheA, cytK, and hblC genes) were characterized among 42 B. cereus isolates with variable frequencies. Detection of the nheA gene showed a high level of 90.4%, followed by the cytK gene in percentage at 50%, and the hblC gene at 47.6%. All examined strains were resistant to Penicillin, Oxacillin, then Cefixime and Ampicillin (85.7%), followed by Nalidixic acid (73.8%), Sulphamethoxazol-Trimethoprim(61.9%), and Oxytetracycline and Cephalotin (52.3%) whilst sensitive to Gentamicin (75%), followed by Enrofloxacin and Erythromycin (50%). Unfortunately, all examined strains are MDR and show 23 resistance patterns, this represents a real health malice for the people of Egypt. The obtained results demonstrated the rise of pathogenic B. cereus, a virulent organism that is multidrug-resistant, in Egypt's retail milk and milk products.