Bacteriological examination for some Gram-negative bacteria (E.coli, Salmonella and Pseudomonas aeruginosa) from 200 samples of bone meal-protein meal, fish meal and poultry residue meal (50 samples for each) obtained from different sources was done. Results revealed that E.coli isolates recovered with an incidence 12% while Pseudomonas aeruginosa
and Salmonella isolates were recovered with an incidence (5% and 3%) respectively. Salmonella serovars isolated were S.Typhimurium, S.Enteritidis and S. Salamae in percent 1.5, 1 and 0.5 % respectively. Pseudomonas aeruginosa serotypes were (A, D and M) while E. coli serotypes were O26, O18, O78 and O157. Bacterial suspension of the isolates were prepared in a concentration of (3x108 cfu/ml) and exposed directly to Gamma rays emitted from cobalt 60 source at room temperature at a dose rate 3-7 kGy/hr, Complete inhibition of bacterial growth was recorded at dose 4 kGy/hr from exposure to Gamma rays .At the same time, the bacterial suspension of the isolates in a concentration of (3x108 cfu/ml) inoculated in
fish meal samples and exposed directly to Gamma rays emitted from cobalt 60 source at room temperature at a dose rate 3-7 kGy/hr, complete sterility of the feed stuff was recorded at a dose 6 kGy/hr exposure to Gamma rays. In conclusion, Gamma radiation of feed samples contaminated with E. coli, P. aeruginosa and Salmonella serovars revealed complete
sterilization and bacteria couldn't be detected by culture resolution.