Date of Award

1-2021

Degree Name

MS in Agriculture - Food Science and Nutrition

Department/Program

Food Science and Nutrition

College

College of Agriculture, Food, and Environmental Sciences

Advisor

Amanda Lathrop

Advisor Department

Food Science and Nutrition

Advisor College

College of Agriculture, Food, and Environmental Sciences

Abstract

For years the issue of food waste has been recognized and quantified; however, food safety issues often go unrecognized as a source of food waste. One objective of this research is to estimate quantities and monetary value of fruits and vegetables implicated in food safety recalls, and thus wasted. Using publicly available data we identified all recalls involving vegetable or fruit commodities contaminated with Listeria monocytogenes, pathogenic E. coli, or Salmonella during 2015-2018. When quantities were provided, monetary value of recalled product was calculated using USDA ERS 2016 average retail prices. Although data limitations only allowed analysis of 17% of the recalls that met the criteria of this study, we estimated an annual loss of 38 million pounds and $61 million in revenue. Overall this shows that food safety issues can result in food waste, therefore mitigation strategies are needed.

There are many ways that produce can become contaminated, however contaminated soils are a potential source of produce contamination and treatments to mitigate this risk while maintaining soil health is lacking. Current biofumigation methods that use glucosinolate hydrolysis products in mustard seed meal to control plant pathogens could also be effective against foodborne pathogens in soil. The purpose of this research is to determine the fate of E. coli O157:H7, Salmonella, and L. monocytogenes in soil treated with Brassica spp seed meal and plant material. Seed meals were successful in reducing pathogen concentrations in soil, significant reductions (p < 0.05) of E. coli O157:H7, L. monocytogenes, and Salmonella were observed in soil over 72 hours with the addition of 1.0 and 1.5 g of mustard seed meal. Increasing the seed meal concentration did not significantly (p > 0.05) increase the observed log reduction for L. monocytogenes or Salmonella, reductions ranged from 5.6 – 5.9 log CFU/g. However, for E. coli O157:H7 seed meal concentration was significant (p < 0.05). A 5.7 log CFU/g decrease was observed when 1.5 g of seed meal was used which was larger than 3.5 log CFU/g reduction observed with 1.0 g. Findings suggest that biofumigation with mustard seed meal could potentially be used to reduce E. coli O157:H7, L. monocytogenes, and Salmonella in contaminated soil.

However, the use of plant material was not as successful as the use of the processed seed meals. In soil or in the absence of soil Brassica spp. plant material at 10% 15%, and 75% significantly increased E. coli O157:H7, L. monocytogenes, and Salmonella concentrations (p < 0.05). The results of these studies support literature indicating Brassica spp. processed plant products, like seed meals or extracts may be a more effective strategy in reducing human pathogen concentrations in contaminated agricultural soils. While the process of Biofumigation using Brassica spp. cover crops has been successful in eliminating plant pests from agricultural soils, due to its low isothiocyanate release efficiency and reactivity in soil organic matter, it may not be sufficient as a soil decontamination method against human pathogens.

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