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Title: THE EFFECTS OF ELECTRON BEAM IRRADIATION ON THE SURVIVAL OF SALMONELLA ENTERICA SEROVAR TYPHIMURIUM AND PSYCHROTROPHIC BACTERIA AND RAW CHICKEN BREASTS STORED AT 4 DEGREE CELSIUS FOR 14 DAYS

Author
item SARJEANT, S - ANIMAL SCI, UNIV OF FLA
item WILLIAMS, S - ANIMAL SCI, UNIV OF FLA
item Hinton Jr, Arthur

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2004
Publication Date: 5/1/2005
Citation: Sarjeant, S.K., Williams, S.K., Hinton Jr, A. 2005. The effects of electron beam irradiation on the survival of salmonella enterica serovar typhimurium and psychrotrophic bacteria and raw chicken breasts stored at 4 degree celsius for 14 days. Poultry Science. 84:955-958.

Interpretive Summary: Fresh chicken meat may be contaminated by bacteria, such as Salmonella, that cause human foodborne diseases and by bacteria that cause spoilage of the meat. Irradiation of foods can kill microorganisms found on foods. In the present study, the ability of irradiation to reduce the number of Salmonella bacteria and spoilage bacteria on chicken breast meat was examined. Salmonella bacteria were placed on fresh chicken breast meat, and the meat was packaged in Styrofoam trays and wrapped with plastic film. The packaged meat was then exposed to different amounts of radiation, and the number of Salmonella that survived the irradiation treatment was determined. Treated meat packages were refrigerated for up to 2 weeks, and then analyzed for the number of Salmonella and spoilage organisms present. Results indicated that irradiation decreased the number of Salmonella on fresh chicken breasts, but the number of Salmonella present increased during refrigerated storage. Also, fewer spoilage bacteria were found on irradiated meat than on meat that was not irradiated. Findings indicate that irradiation may be used to reduce the number of human Salmonella infections associated with eating contaminated chicken and that the amount of time that fresh chicken meat can be stored under refrigeration might be increased by irradiation.

Technical Abstract: The effect of high energy electron beam irradiation on the survival of Salmonella enterica serovar typhimurium and psychrotrophic bacteria on commercial chicken breast meat was evaluated. Fresh chicken breast meat was purchased from a local poultry processor, inoculated with 8 log10 cfu/ml Salmonella, packaged in Styrofoam trays and over wrapped with a polyvinyl chloride film, and subjected to either 0, 1, 2 or 3 kilogray (kGy) dosages of irradiation. The packaged samples were stored at 4ºC and analyzed for S. typhimurium and psychrotrophic organisms at 0, 2, 4, 6, 8, 10, 12, and 14 d of storage. Direct plating and enrichment methods were employed for S. typhimurium analyses. The direct plating method revealed a 4 log reduction in Salmonella for chicken breasts inoculated and treated with 1, 2 and 3 kGy of irradiation. Psychrotrophic counts were conducted at 7ºC for 10 d and 25ºC for 5 d to determine the effect of incubation methods on the recovery of psychrotrophic organisms. The enrichment method resulted in the repair of injured Salmonella cells and an elevated Salmonella typhimurium count for all irradiation dosages, when compared to the data reported for the direct plating method. In general, psychrotrophic counts increased as storage time increased. However, psychrotrophic counts decreased significantly (P < 0.05) as the irradiation dosage increased.