A two-step antimicrobial processing intervention for inactivation of bacteria on produce surface

Authors: Ukuku, Dike; Mukhopadhyay, Sudarsan; Olanya, Modesto; Niemira, Brendan

Submitted to: UJNR Food & Agricultural Panel Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/24/2019
Publication Date: 11/15/2019
Citation: Ukuku, D.O., Mukhopadhyay, S., Olanya, O.M., Niemira, B.A. 2019. A two-step antimicrobial processing intervention for inactivation of bacteria on produce surface. UJNR Food & Agricultural Panel Proceedings. TSukuba, Ibaraki, Japan., Page 31-31.

Interpretive Summary: Inability of one step processing intervention to kill bacterial population on fresh produce led to combining several treatments (antimicrobials + cold plasma + UV-C irradiation) intervention processing steps to kill bacterial pathogens on produce surfaces. Individual treatments were successful in killing bacterial populations on apples and tomatoes surfaces. All treatment combination (antimicrobials + cold plasma and or antimicrobials + UV-C irradiation) tested reduced E. coli, L. monocytogenes and Salmonella bacteria on tomatoes to less than 1 CFU/g and the results suggests that it is a better alternative treatment for controlling and enhancing microbial safety of tomatoes and apples designated for fresh-cut preparation.

Technical Abstract: People are demanding fresh foods without minimal heat treatments, and this has led to consumption of foods contaminated with bacterial pathogens. Fresh fruit and vegetable ranked 4th. in food category responsible for foodborne illnesses in the United States, implicated in 1.2 million illness, 7,100 hospitalizations, 134 human deaths, and $1.4 billion in associated illness costs each year. Enhancing microbial food safety involves a multidimensional approach, and at times, full microbial inactivation is not achieved. In this study, we investigated the efficacy of antimicrobial solution developed in our laboratory, cold plasma and UV-light treatments, individually and as a combination treatment, for inactivation of Salmonella and Listeria monocytogenes inoculated on apple and tomatoes surfaces at 4.8 Log CFU/g, respectively. Antimicrobial treatment alone led to 4 log reduction of each bacterium and cold plasma and UV-light (0.6 kJ/m2) treatments for 1 min led to 1.8 log reduction of Salmonella and Listeria monocytogenes, respectively. When treatments were combined, average bacterial reduction was 4.7 log for antimicrobial and cold plasma and 4.4 log for antimicrobial and UV-light treatments. Surviving bacterial populations on treated apples and tomatoes were below the limit of detection (<2 CFU/g) and population remained unchanged throughout 14 days of storage at 5C. The results indicate that a combination of either treatment procedure stated above would significantly (P<0.05) reduce microbial populations on apples and tomatoes and would enhance the microbial safety of produce like apples and tomatoes.