title: Influence of water activity on inactivation of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in peanut butter by microwave heating.
abstract: This study evaluated the efficacy of a 915 MHz microwave with 3 different electric power levels to inactivate three pathogens in peanut butter with different aw. Peanut butter inoculated with Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium and Listeria monocytogenes (0.3, 0.4, and 0.5 aw) were treated with a 915 MHz microwave with 2, 4, and 6 kW for up to 5 min. Six kW 915 MHz microwave treatment for 5 min reduced these three pathogens by 1.97 to >5.17 log CFU/g. Four kW 915 MHz microwave processing for 5 min reduced these pathogens by 0.41-1.98 log CFU/g. Two kW microwave heating did not inactivate pathogens in peanut butter. Weibull and Log-Linear + Shoulder models were used to describe the survival curves of three pathogens because they exhibited shouldering behavior. Td and T5d values were calculated based on the Weibull and Log-Linear + Shoulder models. Td values of the three pathogens were similar to D-values of Salmonella subjected to conventional heating at 90 °C but T5d values were much shorter than those of conventional heating at 90 °C. Generally, increased aw resulted in shorter T5d values of pathogens, but not shorter Td values. The results of this study can be used to optimize microwave heating pasteurization system of peanut butter.
authors.affiliation: Department of Food and Animal Biotechnology, Center for Food and Bioconvergence, Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 25354, Republic of Korea.
authors.forename: Won-Jae
authors.initials: WJ
authors.lastname: Song
authors.affiliation: Department of Food and Animal Biotechnology, Center for Food and Bioconvergence, Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 25354, Republic of Korea. Electronic address: kang7820@snu.ac.kr.
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kang
mesh_terms: D010367:Arachis / Q000737:chemistry / Q000382:microbiology*; D002079:Butter / Q000382:microbiology* / Q000528:radiation effects*; D019453:Escherichia coli O157 / Q000528:radiation effects*; D005516:Food Microbiology; D006361:Heating; D006801:Humans; D007700:Kinetics; D008089:Listeria monocytogenes / Q000528:radiation effects*; D050296:Microbial Viability; D008872:Microwaves; D061352:Pasteurization / Q000379:methods; D012486:Salmonella typhimurium / Q000528:radiation effects*; D014867:Water
chemical_list: D014867:Water; D002079:Butter
keywords: Foodborne pathogen; Microwave heating; Peanut butter; Water activity