title: Effects of gamma irradiation for inactivating Salmonella Typhimurium in peanut butter product during storage.
abstract: Three types (A, B, and C) of peanut butter product with different water activities (0.18, 0.39, and 0.65 aw) inoculated with a 3-strain mixture of Salmonella Typhimurium were subjected to gamma irradiation (⁶⁰Co) treatment, with doses ranging from 0 to 3 kGy. The inactivation of S. Typhimurium in the 3 types of treated peanut butter product over a 14 day storage period and the influence of storage temperature at 4 (refrigerated) and 25 °C (ambient), and peanut butter product formulation were investigated. Three types of peanut butter product inoculated with S. Typhimurium to a level of ca. 6.6 log CFU/g and subjected to gamma irradiation experienced significant (p<0.05) reductions of 1.3 to 1.9, 2.6 to 2.8, and 3.5 to 4.0 log CFU/g at doses of 1, 2, and 3 kGy, respectively. The time required to reduce S. Typhimurium in peanut butter product to undetectable levels was 14, 5, and 5 days at 25°C after exposure to 3 kGy for products A, B, and C, respectively, and 7 days at 25 °C following exposure to 2 kGy for product C. During storage at 4 and 25 °C, survival of S. Typhimurium was lowest in product C compared to products A and B. Water activity (a(w)) of peanut butter product was likely the most critical factor affecting pathogen survival. When a(w) is reduced, radiolysis of water is reduced, thereby decreasing antimicrobial action. Overall, death was more rapid at 25 °C versus 4 °C for all peanut butter products during 14 day storage. Following gamma irradiation, acid values of peanut butter product were not significantly different from the control, and general observations failed to detect changes in color and aroma, even though lightness observed using a colorimeter was slightly reduced on day 0. The use of gamma irradiation has potential in preventing spoilage of post-packaged food by destroying microorganisms and improving the safety and quality of foods without compromising sensory quality.
authors: Department of Food and Animal Biotechnology, School of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul 151-921, South Korea; Center for Food and Bioconvergence, Seoul National University, Seoul 151-921, South Korea.
authors: Ga-Hee
authors: GH
authors: Ban
authors: Department of Food and Animal Biotechnology, School of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul 151-921, South Korea; Center for Food and Bioconvergence, Seoul National University, Seoul 151-921, South Korea. Electronic address: kang7820@snu.ac.kr.
authors: Dong-Hyun
authors: DH
authors: Kang
mesh_terms: D000143:Acids / Q000032:analysis; D010367:Arachis / Q000382:microbiology*; D015169:Colony Count, Microbial; D003116:Color; D005511:Food Handling; D005514:Food Irradiation / Q000592:standards*; D005516:Food Microbiology; D061353:Food Storage / Q000592:standards*; D005720:Gamma Rays; D050296:Microbial Viability / Q000528:radiation effects*; D012486:Salmonella typhimurium / Q000528:radiation effects*; D013696:Temperature; D013997:Time Factors
chemical_list: D000143:Acids
keywords: Gamma irradiation; Peanut butter product; Salmonella Typhimurium; Storage