Date of Graduation

12-2021

Document Type

Thesis

Degree Name

Master of Science in Food Science (MS)

Degree Level

Graduate

Department

Food Science

Advisor/Mentor

Hettiarachchy, Navam S.

Committee Member

Owens, Casey M.

Second Committee Member

Morawicki, Ruben O.

Keywords

Antimicrobial; Floor Treatment; Food Processing; Hygiene; Pathogens

Abstract

The flooring in a food processing environment can become contaminated with pathogenic bacteria in many ways including foot and equipment traffic, incoming materials, and drain backups. Turmeric (Curcuma longa L.) rhizome powder and seventeen other commercially available powdered floor treatments with a variety of active ingredients including quaternary ammonium compounds (QAC), sodium percarbonate and similar perhydrates (SPC), urea, and borax, were investigated for reducing the levels of pathogens on flooring thereby reducing the risk of cross-contamination from the floor to food contact surfaces. Some of the commercially available floor treatments were Environmental Protection Agency (EPA) registered antimicrobials while others were not but contain chemicals that might provide an antimicrobial effect despite their actual labeled purpose. These substances were evaluated to determine their relative effectiveness against cocktails of Salmonella, Escherichia coli, and Listeria monocytogenes dried onto the surfaces of carriers made from polyurethane-concrete commercial flooring material. Aqueous test solutions were prepared from the minimum mass of the treatment required per m2 from the manufacturer’s instructions diluted in 300 mL sterile water. Potential synergy between turmeric and a percarbonate based commercial floor treatment was investigated at half the previous concentration of each. The inoculated carriers were exposed to the treatment solutions or sterile water control for 10 minutes at room temperature. Viable bacteria were enumerated and log10 reductions versus sterile water were calculated for each treatment and inoculum combination. Mean log10 CFU/carrier reductions (with standard deviations) for Salmonella ranged between 4.29±0.34 for a sodium percarbonate (SPC) based treatment and 0.004±0.23 for turmeric. Reductions of E. coli ranged between 4.81±0.16 for an SPC based treatment and -0.16±0.62 for turmeric. Against L. monocytogenes, reductions ranged from 4.88±0.6 for an SPC based treatment and -0.16±0.15 for turmeric. The results support that among the treatments tested, those containing sodium percarbonate were more effective, turmeric powder alone was less effective, and a percarbonate containing treatment including turmeric powder was not more effective than the commercial treatment alone at half the recommended application rate against the three cocktails of organisms tested.

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