Chemical sanitizer’s effectiveness to eliminate wet multispecies Shiga toxigenic Escherichia coli (STEC) biofilms in the meat industry
| dc.contributor.author | Koti, Kavitha | |
| dc.contributor.examiningcommittee | Bandara, Nandika (Food and Human Nutritional Sciences) | |
| dc.contributor.examiningcommittee | Yang, Chengbo (Animal Science) | |
| dc.contributor.supervisor | Narvaez Bravo, Claudia | |
| dc.date.accessioned | 2024-09-13T14:28:21Z | |
| dc.date.available | 2024-09-13T14:28:21Z | |
| dc.date.issued | 2024-08-07 | |
| dc.date.submitted | 2024-08-08T04:25:38Z | en_US |
| dc.date.submitted | 2024-09-13T14:00:38Z | en_US |
| dc.degree.discipline | Food and Human Nutritional Sciences | |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | Introduction: Shiga toxin-producing Escherichia coli (STEC) are prominent foodborne pathogens known for their ability to form robust biofilms on food contact surfaces, contributing to contamination risks in food processing environments. The objective of the present research investigation was to evaluate the susceptibility of seven STEC strains to different sanitizers in planktonic conditions. Further, the efficacy of sanitizers against STEC single and multispecies biofilms (with lactic acid bacteria and spoilage bacteria) under varying temperatures and surface conditions will be assessed. Methods: The first study examined their responses in planktonic form, single-species, and multispecies biofilms (T1: Carnobacterium piscicola + Lactobacillus bulgaricus, T2: Comamonas koreensis + Raoultella terrigena, T3: Pseudomonas aeruginosa + C. koreensis) cultured in 96-well microplates at 10°C and 25°C, using sanitizers such as Quats, Shypo, SHyd, HyP, and PAA. The second study assessed biocide effectiveness against mature biofilms on polyurethane (TPU) or stainless steel (SS) surfaces at 10°C and 25°C under 60-90% RH, following a standardized cleaning regimen involving detergent application, optional scrubbing, rinsing, and subsequent biocide treatment. Results: The first study found that planktonic cells and single-species biofilms in microplates were highly susceptible to sanitizers, particularly Lactobacillus and Carnobacterium. O157 strains showed resistance to sodium hypochlorite at 25°C (P < 0.05), with PAA demonstrating the highest efficacy in single-species biofilms, followed by Quats, HyP, SHyd, and Shypo (P < 0.05). Multispecies biofilms in microplates were more resistant, especially to SHyd, followed by Quats, HyP, Shypo, and BioDestroy®. In the second study, a triple interaction between mechanical removal, biofilm age, and sanitizer significantly influenced the reduction of O157 on TPU and SS surfaces regardless of the cleaning condition and temperature at 6 and 30 days (P < 0.01). Quats, Shypo, HyP, and SHyd showed reduced effectiveness without prior scrubbing (P < 0.001), whereas BioDestroy® was highly effective, especially on poorly cleaned surfaces. Biofilms aged 6 and 30 days demonstrated greater tolerance to sanitizers compared to 60-day-old biofilms (P < 0.001). Among the T1, T2, and T3 combinations, T2 exhibited the highest resistance to biocides, while O157 within T3 and T1 were more susceptible (P < 0.001). Surfaces not mechanically cleaned achieved a complete reduction of T2+O157 and T3+O157 with Quats and HyP, although survival was observed upon enrichment. Conclusion: This research reveals the intricate interplay of temperature variations, microbial interactions, and effective cleaning protocols in evaluating sanitizer efficacy against STEC within diverse biofilm contexts across food processing surfaces. The findings offer practical strategies for enhancing bacterial control measures in food safety protocols. | |
| dc.description.note | October 2024 | |
| dc.identifier.uri | http://hdl.handle.net/1993/38586 | |
| dc.language.iso | eng | |
| dc.subject | Biofilms | |
| dc.subject | sanitizers | |
| dc.subject | antimicrobial resistance | |
| dc.subject | STEC | |
| dc.subject | E.coli | |
| dc.subject | pseudomonas | |
| dc.subject | multispecies biofilms | |
| dc.subject | EPS | |
| dc.subject | pathogens | |
| dc.subject | tolerance | |
| dc.subject | resistance genes | |
| dc.subject | food spoilage | |
| dc.subject | genome | |
| dc.subject | meat | |
| dc.subject | cattle | |
| dc.subject | food industries | |
| dc.subject | surfaces | |
| dc.subject | food contact surfaces | |
| dc.subject | lactic acid bacteria | |
| dc.title | Chemical sanitizer’s effectiveness to eliminate wet multispecies Shiga toxigenic Escherichia coli (STEC) biofilms in the meat industry | |
| local.subject.manitoba | no | |
| oaire.awardTitle | BCRC | |
| project.funder.identifier | FOS.04.18 | |
| project.funder.name | BCRC |