Modelling the inactivation, survival and growth of Salmonella enterica under osmotic stress considering inoculum phase and serotype.

Autor: Paganini CC; Department of Chemical and Food Engineering, Federal University of Santa Catarina - UFSC, Florianópolis, Brazil., Longhi DA; Federal University of Paraná - UFPR, School of Food Engineering, Jandaia do Sul, Brazil., de Aragão GMF; Department of Chemical and Food Engineering, Federal University of Santa Catarina - UFSC, Florianópolis, Brazil., Carciofi BAM; Department of Chemical and Food Engineering, Federal University of Santa Catarina - UFSC, Florianópolis, Brazil.
Jazyk: angličtina
Zdroj: Journal of applied microbiology [J Appl Microbiol] 2022 May; Vol. 132 (5), pp. 3973-3986. Date of Electronic Publication: 2022 Mar 21.
DOI: 10.1111/jam.15515
Abstrakt: Aims: This study evaluated the behaviour of the Salmonella enterica serotypes in osmotically stressful BHI broth (0.940 ≤ a w  ≤ 0.960), assessing inoculum from two stages of the bacterial life cycle (exponential and stationary) and two temperatures (25°C and 35°C).
Methods and Results: Four S. enterica serotypes (Typhimurium, Enteritidis, Heidelberg and Minnesota) were grown in stressful BHI at 25°C. A mathematical model was proposed for describing the total microbial count as the sum of two subpopulations, inactivating and surviving-then-growing. When submitted to a w of 0.950 and 0.960, all strains showed a decreased count, followed by a period of unchanged count and then exponential growth (Phoenix Phenomenon). Strains inoculated at a w  = 0.940 and 0.945 showed inactivation kinetics only. Cells cultivated at 25°C and inoculated from the exponential phase were the most reactive to the osmotic stress, showing a higher initial population reduction and shorter adaptation period. The proposed model described the inactivation data and the Phoenix Phenomenon accurately.
Conclusions: The results quantified the complex response of S. enterica to the osmotic environment in detail, depending on the inoculum characteristic and serotype evaluated.
Significance and Impact of Study: Quantifying these differences is truly relevant to food safety and improves risk analysis.
(© 2022 Society for Applied Microbiology.)
Databáze: MEDLINE
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