Inactivation of Escherichia coli, Salmonella entericia serova Typhimurium, and Bacillus cereus in roasted grain powder by Radio Frequency Heating

• Published in: Journal of applied microbiology 2020-05
• Main Authors: Jeong, Ki-Ok, Kim, Sang-Soon, Park, Sang-Hyun, Kang, Dong-Hyun
• Format: Article
• Language: English
• ISSN: 1365-2672
• DOI: 10.1111/jam.14705

The objective of this study was to evaluate the antimicrobial effects of Radio frequency (RF) heating and the combination treatment of RF heating with ultraviolet (UV) radiation against foodborne pathogens in roasted grain powder (RGP). Foodborne pathogens inoculated on RGP were subjected to RF heating or RF-UV combination treatments. After 120 s of RF heating, 4.68, 3.89, and 4.54 log reductions were observed for E. coli, S. Typhimurium, and B. cereus vegetative cells, respectively. The combined RF-UV treatment showed synergistic effects of over 1 log unit compared to the sum of individual treatment for E. coli and S. Typhimurium, but not for B. cereus vegetative cells because of their high UV resistance. Germinated B. cereus cells were not significantly inactivated by RF heating (< 1 log CFU g ), and increased heat resistance compared to the vegetative cells was verified with mild heat treatment. Color of RGP were not significantly affected by the RF or RF-UV treatments. Applying RF heating to grain-based food products has advantages for the inactivation of E. coli and S. Typhimurium in RGP. Results of the present study could be used as a basis for determining the treatment conditions for inactivating E. coli and other foodborne pathogens such as S. Typhimurium and B. cereus in RGP.