Document Type : Research article
Authors
1
Dept. of Food Hygiene Fac. Vet. Med., Assiut University
2
Dept. of Food Hygiene, Fac. of Vet. Med., Suez Canal Univ.
3
Animal Health Research Institute, Assiut
Abstract
A total of 200 random samples of pickeled Damietta, pickeled kareish cheese, mish and kishk (50 each) were collected from different markets and shops in Assiut City. The average pH values of the examined samples were 4.64, 5.17, 5.32 and 4.11, while the average values of NaC1% were 9.88, 10.55, 11.81 and 7.32, of the examined samples, respectively. The samples were examined for numbers and types of halophilic bacteria. It was found that all of the examined samples contained (100%) halophilic bacteria using halophilic agar either containing 3% or 10% salt. The average numbers of halophilic bacteria recovered on halophilic agar containing 3% salt were 99x104, 17x104, 29x10, 9x104 /g of the examined pickled Damietta, kareish cheese, mish and kishk samples respectively. Crresponding counts on halophilic agar containing 10% NaCl were 31x10, 62x105, 25x104 and 13x10 g of the examined samples, respectively. Seven hundred (700) isolates were recovered from the examined samples in different percentages. These isolates were identified biochemically as S.aureus, S.epidermidis, Micrococci, B.cereus, B.licheniformis, B. coagulence, B. subtilis, B. mycoids, E. coli and Proteus species. However, S. aureus, Staph.epidermedis, micrococci, E. coli and Proteus species failed to recover from the examined kishk samples. Enterotoxigenicity of S.aureus isolates reveal that 24 (24.8%
out of 97 strains recovered from the examined samples were found to produce enterotoxins A, B, AB, BC and ABC in numbers of 9, 6, 4,3 and 2 strains, respectively. B.cereus could be isolated from pickeled Damietta, pickeled kareish, mish and kishk samples in different percentages. Diarrheal enterotoxin was produced by 38% of the tested B.cereus strains including 18, 9, 6, 5 out of 43, 22, 19 and 16 B.cereus isolates recovered from the examind samples, respectively. The public health hazard of these pathogens and preventive measures were discussed.
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