Improving food safety when traditional lab experiments with pathogens won’t work: corn wet milling and preharvest soil safety on pilot and field scale

When food safety research is conducted with pathogens on lab scale, it requires specialty equipment and personal protection equipment. These laboratories require a Biosafety Level 2 (BSL-2) authorization for working with microorganisms associated with human disease and pose moderate risk to personnel and the environment. In addition, BSL-2 laboratory personnel must receive specific training to handle pathogenic microorganisms (Centers for Disease Control & National Institutes of Health, 2020). This may pose a potential challenge for industry when microbiological research needs to be done their own equipment, as working with pathogens could expose their equipment, fields, or personnel to potential contaminants. Biosafety Level 1 (BSL-1) applies to laboratories that work with microorganisms that are not known to consistently cause disease in immunocompetent adult humans (Centers for Disease Control & National Institutes of Health, 2020), and thus facilitates the ability to study applied food microbiology studies with lower risk to pilot scale or field scale research with industry. A surrogate has similar behavior to a pathogen and can be used in microbiology to study the fate of a pathogen in a specific environment without using the pathogen directly. An indicator microorganism indicates the presence of a potential contaminant, for example fecal contamination, by existing in an environment that could also contain microorganisms relevant to food quality and safety but is nonpathogenic (Sinclair et al., 2012). The Food Safety Modernization Act (FSMA) in the United States is requiring food facilities to have food safety plan in place that includes analysis of hazards and risk-based preventative controls to minimize or prevent the identified hazards (Food and Drug Administration, 2017a). The use of surrogates and indicator microorganisms are useful for the development of food safety plans and preventative controls by aiding in generating datasets while using nonpathogenic, BSL-1 organisms. There are numerous advantages to pilot scale studies; pilot studies typically utilize larger volumes of materials, and more closely simulate full-scale manufacturing processes, and therefore can exceed the capabilities on what can be done on a smaller, lab bench scale. Working exclusively on laboratory scale is a closely controlled environment, which can be useful for proof of concept and working with pathogens directly, but realistic treatment conditions that are difficult to duplicate in a practical sense that would otherwise apply on full-scale operations. In Chapter 2 of this thesis, the use of a BSL-1 surrogate, Enterococcus faecium is used in place of Salmonella during native corn starch production using pilot-scale corn wet milling equipment; E. faecium is reduced by currently existing conditions used for corn starch production and was quantified at each step so that individual producers can use this to assist in the development of the food safety plans in a relevant context to their own operations. In Chapter 3 of this thesis, indicators organisms related to food safety considered BSL-1 such as generic Escherichia coli and total coliforms, and aerobic plate counts which are quality indicatory organisms, are investigated in the context of field-scale soil sampling on produce fields. Results show that hydrated bootie swabs are more successful in detecting the indicator microorganisms than current soil sampling methods.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Food Science & Human Nutrition

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Kealey, Erin Elizabeth

Contributors dc:contributor

• Stasiewicz, Matthew J.
• Banerjee, Pratik
• Margenot, Andrew

• Food Safety
• Surrogate Organism
• Indicator Organism
• Pilot Scale
• Commercial Scale
• Environmental Monitoring
• Produce Safety
• Soil Sampling
• Corn Starch
• Corn Wet Milling

Statement dc:rights

• Copyright 2025 Erin Kealey

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/130007

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F130007