Combining Lactic Acid Spray with Near-Infrared Radiation Heating To Inactivate Salmonella enterica Serovar Enteritidis on Almond and Pine Nut Kernels.
The aim of this study was to investigate the efficacy of near-infrared radiation (NIR) heating combined with lactic acid (LA) sprays for inactivating Salmonella enterica serovar Enteritidis on almond and pine nut kernels and to elucidate the mechanisms of the lethal effect of the NIR-LA combined treatment. Also, the effect of the combination treatment on product quality was determined. Separately prepared S. Enteritidis phage type (PT) 30 and non-PT 30 S. Enteritidis cocktails were inoculated onto almond and pine nut kernels, respectively, followed by treatments with NIR or 2% LA spray alone, NIR with distilled water spray (NIR-DW), and NIR with 2% LA spray (NIR-LA). Although surface temperatures of nuts treated with NIR were higher than those subjected to NIR-DW or NIR-LA treatment, more S. Enteritidis survived after NIR treatment alone. The effectiveness of NIR-DW and NIR-LA was similar, but significantly more sublethally injured cells were recovered from NIR-DW-treated samples. We confirmed that the enhanced bactericidal effect of the NIR-LA combination may not be attributable to cell membrane damage per se. NIR heat treatment might allow S. Enteritidis cells to become permeable to applied LA solution. The NIR-LA treatment (5 min) did not significantly (P > 0.05) cause changes in the lipid peroxidation parameters, total phenolic contents, color values, moisture contents, and sensory attributes of nut kernels. Given the results of the present study, NIR-LA treatment may be a potential intervention for controlling food-borne pathogens on nut kernel products.
Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Institute of GreenBio Science and Technology, Seoul National University, Seoul, South Korea.
Jae-Won
JW
Ha
Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Institute of GreenBio Science and Technology, Seoul National University, Seoul, South Korea Kang7820@snu.ac.kr.
Dong-Hyun
DH
Kang
D002462:Cell Membrane / Q000502:physiology; D005519:Food Preservation / Q000379:methods; D006358:Hot Temperature; D007259:Infrared Rays; D019344:Lactic Acid / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000187:drug effects / Q000528:radiation effects; D050296:Microbial Viability / Q000187:drug effects* / Q000528:radiation effects*; D009754:Nuts / Q000382:microbiology*; D010539:Permeability / Q000528:radiation effects; D028223:Pinus / Q000382:microbiology; D000068181:Prunus dulcis / Q000382:microbiology; D011827:Radiation; D012477:Salmonella enteritidis / Q000187:drug effects* / Q000528:radiation effects*
D019344:Lactic Acid