Thesis
Impact of gas nanobubbles on the efficacy of commonly used antimicrobials in the food industry
Washington State University
Master of Science (MS), Washington State University
05/2020
DOI:
https://doi.org/10.7273/000004118
Handle:
https://hdl.handle.net/2376/125270
Abstract
Nanobubbles (NBs) are defined as fine bubbles with the diameter ranging from 20 to 200 nm with distinctive surfactant properties because of their small size and negatively charged surfaces. This research aimed to study the impact of incorporating NBs in commonly used food antimicrobials (AMs) against Escherichia coli O157:H7 and Listeria monocytogenes. The E. coli and L. monocytogenes experiments were considered independent studies. Each study was conducted as a completely randomized block design with three replications as blocks. Air, carbon dioxide (CO2) and nitrogen (N2) were used to incorporate NBs in the city water. Lactic acid (LA), citric acid (CA), peracetic acid (PAA), and chlorine (Cl2) were used to make the AM solutions. The treatment times of 1.5 and 3.0 min were used to evaluate the log reductions (log CFU/ml) in the respective bacterial cultures. The AM solutions prepared using the city water without NBs acted as the controls for their counterpart AM-NB solutions. Nine-milliliter AM solutions (with or without NBs) were individually taken into sterile test tubes and mixed with 1 ml of E. coli or L. monocytogenes solution grown in brain heart infusion (BHI) broth. At each treatment time, 1 ml of the sample was neutralized using 9 ml of Dey-Engley neutralizing broth, serially diluted using 0.1% peptone solution, and plated on BHI agar. For E. coli, Cl2-CO2 solutions (5.2 logs) resulted in significantly greater log reductions compared to that of Cl2 solutions without NBs (3.8 logs); however, the incorporation of air, CO2 or N2 did not affect the potency of other AM solutions. For L. monocytogenes, PAACO2 solutions (4.4 logs) resulted in significantly greater log reductions compared to that of PAA solutions without NBs (1.7 logs); whereas, the incorporation of air, CO2 or N2 did not affect the potency of any other AM solutions. This study demonstrated that the efficacy of Cl2 and PAA AM solutions could be increased by incorporating CO2 NBs against E. coli and L. monocytogenes in growth media, respectively. Further research should be conducted to study the impact of the incorporation of various gas NBs in different AMs against different pathogens on/in food matrices.
Metrics
Details
- Title
- Impact of gas nanobubbles on the efficacy of commonly used antimicrobials in the food industry
- Creators
- Arshdeep Singh
- Contributors
- Minto Michael (Advisor) - Washington State University, Food Science, School of
- Awarding Institution
- Washington State University
- Academic Unit
- Food Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900890784701842
- Language
- English
- Resource Type
- Thesis