A total of 200 random samples of milk and milk products represented by kareish cheese, yoghurt and icecream (50 for each) were examined microbiologically for the presence of Staphylococcus aureus, its enterotoxigencity and its antibiotic sensitivity. Staphylococcus aureus was isolated from 8 (16%) milk samples, 15 (30%) kareish cheese, 4 (8%) yoghurt and 11 (22%) ice-cream samples. All S. aureus isolates exhibited clumping factor using kits for reliable latex agglutination test. The susceptibility of the isolates was determined for 12 antimicrobial drugs using disc diffusion assay. The majority of strains were susceptible to ofloxacin and ampicillin + sulbactam (100%), vancomycin and tetracycline (94.7%), norfloxacin and sulphamethoxazole + trimethoprim (89.5%), chloramphenicol (73.3%) but they were resistant to oxacillin and metronidazole (100%). Amplification of coagulase gene (coa) using uniplex PCR, staphylococcal enterotoxin genes (sea, seb, sec, sed and see) and methicillin-resistant S. aureus (mecA) gene using multiplex PCR revealed that, 11/11(100%) of the examined samples were positive for both coa and mecA genes. While, sea produced by 5 (45.45%) strains, sec and sed produced by 4 (36.36%) strains and seb and see were not produced by any strains.

Contamination of fish by fungi is considered one of the most serious causes of losses in aquaculture. Therefore, our study was firstly aimed to screen the fungal status of two commonly consumed fish species in Egypt, Tilapia nilotica and Mugil cephalus. Secondly, an experimental trial to investigate the antifungal effect of natamycin on Tilapia nilotica. A total of 60 fish samples including Tilapia nilotica and Mugil cephalus (30 of each) were randomly collected from various retail markets and shops at dissimilar sanitation levels at Kafrelsheikh Governorate, Egypt during the winter season, 2018. All samples were examined for fungal contamination. Tilapia nilotica and Mugil cephalus samples showed average mould counts of 3.63×10 2 and 1.65×10 2 CFU/g, respectively. Nine fungal species were isolated from two fish species. Seven and five species were isolated from Tilapia nilotica Mugil cephalus, respectively. The highest prevalent fungal species isolated from the two fish was Aspergillus flavus. Natamycin showed significant antifungal properties in a concentration-dependent manner. Thus, efficient hygienic handling, rapid cooling of fish can reduce the fungal contamination of fish. In addition, we highly recommend soaking or spraying fish with natamycin solution as an efficient strategy in reducing the fungal load of raw fish.

Two hundred random samples of milk, kareish cheese, yoghurt and ice-cream (50 for each) were examined microbiologically for the presence of Clostridium perfringens, their enterotoxigencity and their antibiotic sensitivity. Clostridium perfringens was isolated from 3 (6%) milk samples, 4 (8%) kareish cheese samples and it could not be isolated from any examined samples of yoghurt and ice-cream. The majority of C. perfringens isolates recovered from milk and milk products were susceptible to ofloxacin, ampicillin + sulbactam and norfloxacin (100%), vancomycin, tetracycline, metronidazole and amoxicillin + clavulinic acid (83.3%) and clindamycin (66.7%). The majority were resistant to cephalothin (100%), sulphamethoxazole + trimethoprim (83.3%), oxacillin and chloramphenicol (66.7%). Molecular studies using multiplex PCR technique for detection of alpha toxin gene and C.perfringens types "A" enterotoxin gene revealed that the 7 isolates of C. perfringens (100%) were positive for alpha toxin gene and only 2 out of 7 isolates (28.57%) were positive for enterotoxin gene .

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