الفهرس 
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Abstract
Many countries restrict the use of offal for reasons of food safety and quality. Foodborne diseases are a major public health problem with growing concern due to contamination of offal by pathogenic microorganisms because of poor hygiene management systems in abattoirs, improper heat treatments during storage and processing or post process contamination.
A total of ninety random samples of some edible beef offal’s; heart, liver and kidney from cow and buffalo carcases (15 of each) were subjected to microbiological examination for APC, psychrophilic bacterial count, Enterobacteriaceae count, Coliforms count, mould and yeast count, isolation and identification of E. coli and Salmonellae from central abattoir at Damanhour Government. On the other hand, detect the effect of chilling, thawing and freezing on microbial profile as well as the effect of boiling, steaming and roasting on microbial profile of some beef offal.
The result revealed that:-
Part (1): microbiological examination of beef offal:
The mean values of aerobic bacterial count of heart, liver and kidney from cow samples were 1.0×106, 1.8×106 and 1.3×106 and from buffalo samples were 1.1×106, 1.0×106 and 1.4×106 cfu/ cm2, respectively. According to microbiological limits outlined by (ES, 2005); aerobic bacterial count must not be exceeded (105). So; the unaccepted heart, liver and kidney from cow samples were 14(93.33%), 15(100%) and 13(86.67%), and from buffalos samples were 13(86.67%), 13(86.67%) and 10(66.67%), respectively.
The mean values of psychrophilic bacterial count of heart, liver and kidney from cow samples were 4.4×102, 2.9×102 and 5.0×10 and from buffalo samples were 1.5×103, 2.0×102 and 3.0×102 cfu/ cm2, respectively.
The mean values of Enterobacteriaceae count of heart, liver and kidney from cow samples were 9.7×103, 9.9×103 and 3.7×104 and from buffalo samples were 1.6×104, 7.8×103 and 1.5×104 cfu/ cm2, respectively.The mean values of Coliforms count of heart, liver and kidney from cow samples were 2.4×103, 2.8×103 and 9.0×103 and from buffalo samples were 4.0×103, 1.1×104 and 2.6×103 cfu/ cm2, respectively. According to microbiological limits outlined by (EOS, 2005); Coliforms count must not exceed (102). So; the unaccepted heart, liver and kidney from cow samples were 8(53.33%), 8(53.33%) and 4(26.67%), and from buffalo samples were 12(80%), 8(53.33%), and 8(53.33%), respectively.
The mean values of mould count of heart, liver and kidney from cow samples were 1.1×103, 1.3×103 and 2.5×102 and from buffalo samples were 1.8×102, 1.2×102 and 9.5×10 cfu/ cm2, respectively. According to microbiological limits outlined by (EOS, 2005); offal must be free from mould. So; the unaccepted heart, liver and kidney from cow samples were 11(73.33%), 13(86.67%) and 11(73.33%), and from buffalo samples were 13(86.67%), 14(93.33%) and 12(80%), respectively.
The mean values of yeast count of heart, liver and kidney from cow samples were 1.2×103, 6.0×102 and 2.2×102 and from buffalo samples were 1.8×102, 2.4×102 and 4.9×102 cfu/ cm2, respectively. According to microbiological limits outlined by (EOS, 2005); offal must be free from yeast. So; the unaccepted heart, liver and kidney from cow samples were 7(46.67%), 6(40%) and 3(20%), and from buffalo samples were 4(26.67%), 4(26.67%) and 3(20%), respectively.
According to microbiological limits outlined by (EOS, 2005); edible offal must be Free from E. coli; the incidence and serotyping of identified E. coli isolated from cow’s heart were 6 samples (40%); 2(EPEC), 3(EHEC) and 1(ETEC), and from cow’s liver were 3 samples (20%); 1(EPEC), 1(EHEC) and 1(EIEC), and from cow’s kidney were 2 samples (13.33%); 1(EHEC) and 1(ETEC). While buffalo’s heart were 3 samples (20%); 1(EPEC), 1(EHEC) and 1(ETEC), and buffalo’s liver were 3 samples (20%); 1(EPEC), 1(ETEC) and 1(EIEC), and buffalo’s kidney was 1 sample (6.67); (EPEC).
According to microbiological limits outlined by (EOS, 2005); edible offal must be Free from Salmonella; the incidence and serotyping of identified Salmonella isolated from cow’s heart were 4 samples (26.67 %); 1(S. Typhimurium), 1(S. Muenster), 1(S. Enteritidis) and 1(S. Virchow), and from cow’s liver were 8 samples (53.33 %); 4(S. Typhimurium), 2(S. Enteritidis), 1(S. Kentuchy) and 1(S. Anatum), and from cow’s kidney were 4 samples (26.67 %); 2(S. Typhimurium) and 2(S. Enteritidis). While buffalo’s heart were 3 samples (20%); 2(S. Enteritidis) and 1(S. Kentuchy), and from buffalo’s liver were 3 samples (20%); 1(S. Typhimurium), 1(S. Virchow) and 1(S. Chester), and from buffalo’s kidney were 4(26.67 %); 2(S. Typhimurium) and 2(S. Enteritidis).
Part (2): Experimental work
The organoleptic signs of spoilage were appeared at 12 day of chilling in cow’s heart and at 15 day of chilling in cow’s liver and kidney samples.The Aerobic bacterial counts, Enterobacteriaceae counts as well as mould and yeast counts increased with time of chilling. The mean values of Aerobic bacterial counts during zero, 3, 6 and 9 day of chilling for examined cow’s heart samples were 2.1 × 105, 4.1 × 104, 1.6 × 105and 3.0 × 105, during zero, 3, 6, 9 and 12 day of chilling for examined cow’s liver were 6.1 × 105, 1.6 × 105, 4.0 × 105, 7.8 × 105 and 1.6 × 106, and for examined cow’s kidney were 7.5 × 105, 1.6 × 105, 7.0 × 105, 1.1 × 106 and 1.6 × 106 cfu/g, respectively.
The mean values of Enterobacteriaceae counts during zero, 3, 6 and 9 day of chilling for examined cow’s heart were 7.5 × 102, 7.0 × 102, 2.3× 103 and 3.1 × 103, during zero, 3, 6, 9 and 12 day of chilling for examined cow’s liver were 4.4 × 102, 1.0 × 102, 1.1 × 103, 4.1 × 103 and 1.9 × 104, and for examined cow’s kidney were 1.5 × 103, 1.4 × 103, 1.9 × 103, 1.3 × 104 and 6.9 × 104 cfu/g, respectively.
The mean values of Mould counts during zero, 3, 6 and 9 day of chilling for examined cow’s heart were 3.2 × 102, 1.5 × 102, 1.8 × 103 and 2.1 × 103, during zero, 3, 6, 9 and 12 day of chilling for examined cow’s liver were 2.8 × 102, 2.0 × 102, 6.0 × 102, 1.1 × 103 and 1.2 × 103 and for examined cow’s kidney were 5.2 × 102, 1.4 × 102, 1.1 × 103, 1.2 × 103 and 1.8 × 103 cfu/g, respectively.
The mean values of Yeast counts during zero, 3, 6 and 9 day of chilling for examined cow’s heart were 3.0 × 103, 3.0 × 103, 4.0 × 104 and 2.2 × 104, during zero, 3, 6, 9 and 12 day of chilling for examined cow’s liver were 1.6 × 104, 3.0 × 103, 1.3 × 104, 2.1 × 104 and 1.9 × 104 and for examined cow’s kidney were 3.0 × 103, 1.2 × 103, 3.5 × 103, 3.6 × 104 and 1.0 × 104 cfu/g, respectively.
The percent of drip loosed after 5, 10, 15, 20 and 30 days of freezing and thawing for cow’s heart were 7.35, 8.25, 9.28, 10.55 and 11.08 %, and for cow’s liver were 1.26, 4.18, 4.62, 5.72 and 6.07 %, and for cow’s kidney were 2.33, 3.22, 3.97, 4.14 and 4.95 %, respectively.The mean values of Aerobic bacterial counts during zero, 5, 10, 15, 20 and 30 day of freezing for examined cow’s heart were 2.1 × 105, 5.5 × 104, 6.1 × 104, 1.3 × 105, 1.6 × 105 and 3.5 × 105, and for examined cow’s liver were 6.1 × 105, 1.6 × 104, 9.7 × 104, 4.5 × 105, 7.0 × 105 and 1.0 × 106, and for examined cow’s kidney were 7.5 × 105, 1.5 × 104, 8.3 × 104, 1.6 × 105, 7.4 × 105 and 1.1 × 106 cfu/g, respectively.
The mean values of Enterobacteriaceae counts during zero, 5, 10, 15, 20 and 30 day of freezing for examined cow’s heart were 7.5 × 102, 5.5 × 102, 1.3 × 103, 2.5 × 103, 2.3 × 103 and 1.2 × 103 , and for examined cow’s liver were 4.4 × 102, 3.0 × 102, 1.7 × 103, 6.5 × 102, 5.5 × 102 and 6.0 × 102 , and for examined cow’s kidney were 1.5 × 103, 1.1 × 103, 2.8 × 103, 5.0 × 102, 7.5 × 102 and 1.8 × 103 cfu/g, respectively.
The mean values of mould counts during zero, 5, 10, 15, 20 and 30 day of freezing for examined cow’s heart were 3.2 × 102, 1.8 × 103, 4.4 × 103, 5.1 × 103, 3.1 × 103 and 6.0 × 102, and for examined cow’s liver were 2.8 × 102, 6.0 × 102, 7.0 × 102, 6.5 × 102, 2.0 × 102 and 2.0 × 102, and for examined cow’s kidney were 5.2 × 102, 1.2 × 103, 3.8 × 103, 1.1 × 103, 5.5 × 103 and 3.0 × 102 cfu/g, respectively.
The mean values of yeast counts during zero, 5, 10, 15, 20 and 30 day of freezing for examined cow’s heart were 3.0 × 103, zero, zero, 4.1× 104, 1.6 × 104 and 2.2 × 103, and for examined cow’s liver were 1.6 × 104, 7.0 × 102, zero, zero, 1.1 × 104 and zero and for examined cow’s kidney were 3.0 × 103, zero, zero, 1.1 × 103, zero and zero cfu/g, respectively.
The reduction percent of aerobic bacterial count after boiling, steaming and roasting for cow’s heart were 99.62, 98.14 and 97.52%, and for cow’s liver were 97.47, 97.70 and 97.08%, and for cow’s kidney were 99.07, 98.84 and 98.55%, respectively.
The reduction percent of Enterobacteriaceae count after boiling, steaming and roasting for cow’s heart were 100, 81.33 and 13.33%, and for cow’s liver were 96.36, 97.27 and 98.75%, and for cow’s kidney were 100, 100 and 100%, respectively.
The reduction percent of mould count after boiling, steaming and roasting for cow’s heart were 82.81, 46.87 and 46.87%, and for cow’s liver were 76.05, 61.97 and 49.29%, and for cow’s kidney were 64.70, 41.17 and 29.41%, respectively The reduction percent of yeast count after boiling, steaming and roasting for cow’s heart were 100, 100 and 100%, and for cow’s liver were 100, 100 and 41.17%, and for cow’s kidney were 100, 100 and 100%, respectively.
from these results, the microbial profiles of some edible beef offal’s were discussed according to Egyptian Standard Specification and the public health importance of different methods of preservations and heat treatments to minimize the risk of food poisoning cases to humans as well as some recommendations for the housewife during cooking including; restrict hygienic steps when dealing with offal and make boiling or steaming then roasting to minimize microbial load and prevent post process contamination.
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