Impact of “Deep Cleaning” sanitization on natural biofilm communities and the survival of Salmonella enterica

Authors: Wang, Rong; Bosilevac, Joseph - Mick

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/2/2022
Publication Date: 11/13/2022
Citation: Wang, R., Bosilevac, J.M. 2022. Impact of “Deep Cleaning” sanitization on natural biofilm communities and the survival of Salmonella enterica. [Abstract]. American Society of Microbiology (ASM) Conference on Biofilms 2022. November 13-17, 2022, Charlotte, NC, Control NO. 2022-A-75-ASM-BIO.

Interpretive Summary:

Technical Abstract: Background: Salmonella enterica is a leading cause of foodborne illness in the U.S. Previous studies suggested that certain S. enterica serovars may be better at adapting to the environment with stronger survival ability via mixed biofilm formation and subsequently, a higher chance of causing food contamination. In the meat industry, one action taken to address pathogen contamination is a Deep-Cleaning (DC) sanitization of the entire processing plant environment that many large processors perform annually or semiannually. However, the immediate and long-term impact of such procedure on natural biofilm disruption and pathogen colonization is unknown. Here we investigated the impact of DC sanitization on environmental biofilms and the subsequent S. enterica colonization and stress tolerance. Method: Floor drain samples containing environmental microorganisms were collected from various areas at a meat plant with S. enterica prevalence before, 1 week, and 4 weeks after DC sanitization. Biofilm formation by microorganisms in 12 drain samples without Salmonella presence was tested on 96-well plates with crystal violet staining under processing temperature (7oC). The ability of the samples to recruit and/or protect from quaternary ammonium compound (QAC) treatments co-inoculated S. enterica strains was determined. The community structure of each drain sample was determined through 16S metagenomic sequencing and analysis. Results: Post-DC samples collected from 8 drains formed significantly higher biofilms than the respective pre-DC samples. Salmonella colonization exhibited no difference between the pre- and post-DC biofilms at each drain location. However, Salmonella survival in QAC-treated pre- and post-DC mixed biofilms varied depending upon the drain locations and higher survival was positively correlated with the biofilm matrix. Results of 16S metagenomic sequencing exhibited community structure shift which might be associated with the phenotype of biofilm formation and Salmonella tolerance in the environment. Conclusion: DC sanitization may disrupt the pre-existing microbial community and alter the natural population composition. Disruption of the environmental biofilms may have unexpected effects due to the resulting lack of competition within the multispecies community and the survival or recruitment of species with high colonizing capability.