Combined Effect of Temperature and Relative Humidity on the Survival of Salmonella Isolates on Stainless Steel Coupons

Abstract

The survival on stainless steel of ten Salmonella isolates from food factory, clinical and veterinary sources was investigated. Stainless steel coupons inoculated with Salmonella were dried and stored at a range of temperatures and relative humidity (RH) levels representing factory conditions. Viability was determined from 1 to 22 days. Survival curves obtained for most isolates and storage conditions displayed exponential inactivation described by a log-linear model. Survival was affected by environmental temperatures and RH with decimal reduction times (DRTs) ranging from <1 day to 18 days. At 25 °C/15% RH, all isolates survived at levels of 10 3 to 10 5 cfu for >22 days. Furthermore, temperatures and RH independently influenced survival on stainless steel; increasing temperatures between 10 °C and 37 °C and increasing RH levels from 30-70% both decreased the DRT values. Survival curves displaying a shoulder followed by exponential death were obtained for three isolates at 10 °C/70% RH. Inactivation kinetics for these were described by modified Weibull models, suggesting that cumulative injury occurs before cellular inactivation. This study highlights the need to control temperature and RH to limit microbial persistence in the food manufacturing environment, particularly during the factory shut-down period for cleaning when higher temperature/humidity levels could be introduced.

Publication DOI: https://doi.org/10.3390/ijerph19020909
Divisions: College of Health & Life Sciences
College of Health & Life Sciences > School of Biosciences > Cell & Tissue Biomedical Research
College of Health & Life Sciences > School of Biosciences
College of Health & Life Sciences > Chronic and Communicable Conditions
Additional Information: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
Uncontrolled Keywords: Food-manufacturing,Humidity,Salmonella,Stainless steel,Survival,Temperature,Pollution,Public Health, Environmental and Occupational Health,Health, Toxicology and Mutagenesis
Publication ISSN: 1660-4601
Full Text Link:
Related URLs: https://www.mdp ... 0-4601/19/2/909 (Publisher URL)
http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2022-01-14
Accepted Date: 2021-12-13
Authors: Bashir, Amreen (ORCID Profile 0000-0002-0428-0922)
Lambert, Peter A. (ORCID Profile 0000-0002-8243-2741)
Stedman, Yvonne
Hilton, Anthony C. (ORCID Profile 0000-0001-8025-5270)

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