Graduate Studies

 

First Advisor

Curtis L. Weller

Second Advisor

Yulie Meneses

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Food Science and Technology

Date of this Version

7-2024

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College of the University of Nebraska in partial fulfillment of requirements for the degree of Doctor of Philosophy

Major: Food Science and Technology

Under the supervision of Professor Curtis L. Weller and Yulie Meneses

Lincoln, Nebraska, July 2024

Comments

Copyright 2024, Basim M. Alohali. Used by permission

Abstract

The work of the dissertation investigated the efficacy of foam-based decontamination treatments to enhance microbial safety in Roma tomatoes, specifically targeting natural microflora and Salmonella contamination. Growing concerns over foodborne illnesses linked to fresh tomatoes and the limitations of conventional decontamination techniques, such as organic matter built-up and limited microbial reduction, are addressed. The primary objectives were to characterize the physiochemical properties of foams formed using various concentrations of Tween 20 (T20) and sodium dodecyl sulfate (SDS) with and without the addition of sodium hypochlorite (NaOCl) and peracetic acid (PAA), compare the efficacy of foam and traditional dump tank (DT) washing methods in removing natural contaminants, and evaluate the performance of NaOCl and PAA in both foam and DT methods for reducing Salmonella on tomato surfaces. The research employed a combination of physicochemical characterization parameters, efficacy study on the natural microflora, and inoculation study to assess the decontamination efficacy. Findings reveal that foam decontamination provides superior microbial reduction and enhances sanitizer efficacy better than the traditional DT method. Specifically, NaOCl combined with T20 in foam form demonstrated significant reductions (p<0.05) in Salmonella counts and natural microflora on Roma tomato surfaces over DT treatments. The study highlights the potential of foam-based decontamination as a more effective alternative to a conventional DT washing method, offering practical implications for enhancing tomato safety in the fresh produce industry.

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