Abstract
A total of 100 random samples of some edible beef offal represented by liver, heart, lung and spleen (25 of each) were subjected to bacteriological examination for Mesophilic bacterial count, Enterobacteriaceae count, Coliforms count, Staphylococcal count, the incidence of S. aureus and detection of enterotoxin genes of S. aureus to evaluate their quality. The mean value of Mesophilic bacterial count / g of liver, heart, lung and spleen were 3.9×104, 3.6×104, 3.03×104 and 5.4×104 cfu/g, respectively. The mean value of Enterobacteriaceae count / g of liver, heart, lung and spleen were 2.3×104, 1.4×104, 1.2×104 and 1.5×104 cfu/g, respectively. The mean value of Coliforms count / g of liver, heart, lung and spleen were 6.4×102, 5.6×102, 6.1×102 and 8.2×102 MPN/g, respectively. The mean value of Staphylococci count / g of liver, heart, lung and spleen were 1.1×102, 1.1×102, 1.3×102 and 1.7×102 cfu/g, respectively. The incidence of S. aureus isolated from examined liver, heart, lung and spleen samples were 36%, 44%, 64% and 32%, respectively. Analysis of the PCR products obtained from amplification reaction of extracted DNA from 10 identified S. aureus strains in this study for detection of enterotoxins genes by agarose gel electrophoresis revealed that the specific band for SEA gene (120bp) was detected in 3(30%) one from liver, heart and spleen out of 10 isolates, while the specific band for SEB gene (478bp) was not detected in any isolate. The specific band for SEC gene (257bp) was detected in 1(10%) from lung out of 10 isolates, also the specific band for SED gene (317bp) was detected in 1(10%) from lung out of 10 isolates. The specific band for SEA, SEC genes (120bp, 257bp) was detected in 1(10%) from spleen out of 10 isolates.

Key words: Enterobacteriaceae, S. aureus, Coliforms, edible beef offal, Enterotoxin genes.