Title: Effects of combination of ultraviolet light and hydrogen peroxide on inactivation of Escherichia coli O157:H7, native microbial loads, and quality of button mushrooms Authors
|Guan, Wenqiang -|
|Yan, Ruixiang -|
Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 25, 2013
Publication Date: December 1, 2013
Citation: Guan, W., Fan, X., Yan, R. 2013. Effects of combination of ultraviolet light and hydrogen peroxide on inactivation of Escherichia coli O157:H7, native microbial loads, and quality of button mushrooms. Food Control. 34:554-559. Interpretive Summary: Mushrooms are prone to microbial spoilage and browning during processing and storage. This study investigated the effects of ultraviolent light (UV) and hydrogen peroxide on microbial population and product quality of mushrooms during 14 days of cold storage. Results showed that combination of UV light and hydrogen peroxide was the best treatment to maintain quality of button mushrooms while inactivating 86% of E. coli O157:H7 inoculated on the mushroom. The combine treatment has a potential to be used by the mushroom industry to reduce quality deterioration while marginally enhancing microbial safety of mushrooms.
Technical Abstract: Mushrooms are prone to microbial spoilage and browning during growing and processing. Ultraviolet light (UV-C) has been used as an alternative technology to chemical sanitizers for food products. Hydrogen peroxide is classified as generally recognized as safe for use in foods as a bleaching and antimicrobial agent, and could control the bacterial blotch and browning of mushrooms. This study investigated the effects of water wash (control), 3% hydrogen peroxide wash, 0.45 kilojoules per square meter UV, and combination of hydrogen peroxide and UV on microbial loads and product quality of mushrooms during storage for 14 days at 4 C. Additionally, the inactivation of Escherichia coli O157:H7 inoculated on mushrooms was determined. Results showed that water wash, hydrogen peroxide, UV and the combined treatment resulted in 0.44, 0.77, 0.85, and 0.87 logs CFU/g reduction of E. coli O157:H7, respectively. Hydrogen peroxide, UV and the combination reduced total aerobic plate counts on the surface of mushrooms by 0.2-1.4 logs CFU/g compared to the control, while there was no significant difference among the three treatments during storage. After storage, hydrogen peroxide maintained the brightest color of mushrooms, and mushrooms treated with UV had similar L* and a* values as the control while mushrooms treated with the combination of hydrogen peroxide and UV had higher L* (lighter) and lower a* (less brown) values than the control. Compared to water wash, all the treatments inhibited lesion development on the mushroom surface on day 14. The combination of hydrogen peroxide and UV achieved the best overall dual control of lesion and browning. There was no significant difference in ascorbic acid and total phenolic content among the treatments. Overall our results suggested that the combination of hydrogen peroxide and UV reduced microbial loads, and extended storage life by keeping bright color and reducing lesion development without causing deterioration in nutritional quality of button mushrooms. Therefore, when properly utilized, the combination of hydrogen peroxide and UV could potentially be used for maintaining postharvest quality while marginally reducing populations of E. coli O157:H7 and background microflora.