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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Microbial and Chemical Food Safety » Research » Publications at this Location » Publication #304524
Title: Natural surface coating to inactivate Salmonella enterica Serovar Typhimurium and maintain quality of cherry tomatoes

Author
item YUN, JUAN - Tianjin University Of Science And Technology
item Fan, Xuetong
item LI, XIHONG - Tianjin University Of Science And Technology
item Jin, Zhonglin
item JIA, XIAOYU - Tianjin University Of Science And Technology
item Mattheis, James

Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2014
Publication Date: 1/16/2015
Citation: Yun, J., Fan, X., Li, X., Jin, Z.T., Jia, X., Mattheis, J.P. 2015. Natural surface coating to inactivate Salmonella enterica Serovar Typhimurium and maintain quality of cherry tomatoes. International Journal of Food Microbiology. 193:59-67.

Interpretive Summary: A number of Salmonella outbreaks have been linked with fresh tomato fruit in recent years. Effective intervention technologies are needed to minimize the risk of pathogens on tomatoes. In this study, coatings consisting of natural compounds including essential oils and zein, a corn protein, were formulated and applied onto cherry tomatoes. Results showed that coating containing cinnamon oil not only reduced population of Salmonella on tomatoes by more 99.99% but also maintained firmness and ascorbic acid content and decreased weight loss during storage. The natural surface coating shows promise for enhancing microbial safety and improving quality of tomato fruit.

Technical Abstract: The objectives of the present study were to investigate the effectiveness of zein-based coatings in reducing populations of Salmonella enterica serovar Typhimurium and preserving quality of cherry tomatoes. Tomatoes were inoculated with a cocktail of S. Typhimurium LT2 plus three mutants on the smooth surface and stem scar. The zein-based coatings with and without cinnamon and mustard essential oil (up to 20%) or a commercial wax formulation were applied onto tomatoes and the treated fruit were stored at 10C for up to 3 weeks. Populations of S. Typhimurium decreased with increased essential oil concentration and storage duration. S. Typhimurium populations on the smooth surface were reduced by 4.59 and 2.84 log CFU/g by the zein coatings with 20% cinnamon and 20% mustard oil, respectively, 5 hours after coating. The same coating reduced populations of S. Typhimurium to non-detectable levels (detection limit: 1 log CFU/g) on the stem scar area of tomato during 7 days storage at 10C. Salmonella populations on fruit were not reduced by coating with the commercial wax. All of the coatings resulted in reduced weight loss compared with uncoated control. Compared with the control, loss of firmness and ascorbic acid during storage were prevented by all of the coatings except the zein coating with 20% mustard oil which enhanced softening. Color was not consistently affected by any of the coating treatments during 21 days of storage at 10C. The results suggest that the zein-based coating containing cinnamon oil might be used to enhance microbial safety and quality of tomato.