Semester

Spring

Date of Graduation

2022

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Human Nutrition and Foods

Committee Chair

Cangliang Shen

Committee Member

Kristen Matak

Committee Member

Annette Freshour

Abstract

Introduction: Due to multi-state outbreaks of listeriosis on apples in 2015, 2017, and 2019, Listeria Monocytogenes (L. monocytogenes) has been deemed an emerging, under researched pathogen by the USDA-NIFA. Therefore, this study evaluated the efficacy of SaniDate 5.0®’s (SD) ability to inactivate L. Monocytogenes on apples when delivered through electrostatic sprayer (ES), garden sprayer (GS), and dip methods.

Methods: Organic apples were dip-inoculated with L. monocytogenes for 5 min and then dried for 10 min. Once dried, the inoculated apples were untreated (control), sprayed with water only, or treated with SD, 0.0064, 0.1, 0.25 and 0.50% for 20 s via GS, ES, or dip. Then the apples were drained (2 min) and placed in a sterile sample bag with 100 ml TSB and shaken for 30 sec. Samples were later 10 or 100-fold serially diluted in 0.1% BPW and spread plated on MOX agar plates, followed by incubation for 48 hrs at 37°C and enumeration. The Mixed Model Procedure of SAS (p=0.05) was used to analyze the reduction of L. monocytogenes on cultivars (2 replicates/6 samples/replicate) under different delivery methods, concentrations, and interactions.

Results: Results indicated dip was the most effective antimicrobial delivery method compared to GS and ES and reductions of L. monocytogenes were greatest (P < 0.05) when apples were treated with 0.50% SD.

Significance: Results suggested that applying 0.5%SD through dipping methods are effective at inactivating pathogens on apples, thus reducing the risk for future listeriosis outbreaks.

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