Abstract: Eight isolates of Salmonella typhimurium were contaminated different sources of meat, poultry products and caused deadly diseases in humans. SDS-polyacrylamide gel electrophoretic technique showed that the protein banding patterns of Salmonella typhimurium. Isolates were more similar in the upper part of the gel. While difference were clearly detected in the lower part of the gel. The protein band of 289 KDa was a common protein band in all isolater of Salmonella typhimurium isolates. The similarity coefficient among Salmonella typhimurium protein profiles ranged from 0.43 to 0.63. By studying plasmid profiles to all isolates, it showed that the intensity of the extracted plasmids from Salmonella typhimurium No. 4. is much denser than others which indicate that there are more copie number of plasmids which could be related to the resistance of this strains. Further study on the isolate No. 4. The effect of irradiation on the viability of bacterial cell which occur drops in the viable count of bacteria in response to increasing doses of gamma irradiation from (0-1.0 KGY) and the D10 value was calculated which equal to 0.561 KGY. Decrease in viable cell number when heating times were extended to 2 min at 65°C. Antibiotic profiles of isolate No. 4 was detected against ten different antibiotic (Imipenem, ampicilin/sulbactum, amoxicillin, nitrofurantion, gentamycin, tobramycin, ofloxacin, cefotaxime cefaclor and chloromphenicol). Detection of MICs by E-test Imipenem. The most effective essential oils were garlic, carvacrol, thyme and thymol. Heating without irradiation caused destabitization of the cytoplasmic membrane allowing penetration of hydrophobic dye. Further, the lethality of heating followed by irradiation for S. typhimurium was additive, reflecting irradiation induced DNA-damage and heat induced membrane destabilization, but when irradiation preceded heating, more cell were inactivated because of heat- inactivating radiation damage DNA. The transmission electron microscope indicate the variation on the effect of radiation heat treatment and combined radiation and heat. The amino acid contents detected that glutamic acid was the dominant.