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Estimating Listeria monocytogenes Growth in Ready‐to‐Eat Chicken Salad Using a Challenge Test for Quantitative Microbial Risk Assessment
Author(s) -
Bernardo Rita,
Barreto António Salvador,
Nunes Telmo,
Henriques Ana Rita
Publication year - 2020
Publication title -
risk analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.972
H-Index - 130
eISSN - 1539-6924
pISSN - 0272-4332
DOI - 10.1111/risa.13546
Subject(s) - listeria monocytogenes , food science , test (biology) , risk assessment , environmental health , microbiology and biotechnology , biology , risk analysis (engineering) , business , medicine , computer science , computer security , bacteria , ecology , genetics
Currently, there is a growing preference for convenience food products, such as ready‐to‐eat (RTE) foods, associated with long refrigerated shelf‐lives, not requiring a heat treatment prior to consumption. Because Listeria monocytogenes is able to grow at refrigeration temperatures, inconsistent temperatures during production, distribution, and at consumer's household may allow for the pathogen to thrive, reaching unsafe limits. L. monocytogenes is the causative agent of listeriosis, a rare but severe human illness, with high fatality rates, transmitted almost exclusively by food consumption. With the aim of assessing the quantitative microbial risk of L. monocytogenes in RTE chicken salads, a challenge test was performed. Salads were inoculated with a three‐strain mixture of cold‐adapted L. monocytogenes and stored at 4, 12, and 16 °C for eight days. Results revealed that the salad was able to support L. monocytogenes’ growth, even at refrigeration temperatures. The Baranyi primary model was fitted to microbiological data to estimate the pathogen's growth kinetic parameters. Temperature effect on the maximum specific growth rate ( μ max ) was modeled using a square‐root‐type model. Storage temperature significantly influenced μ max of L. monocytogenes ( p < 0.05). These predicted growth models for L. monocytogenes were subsequently used to develop a quantitative microbial risk assessment, estimating a median number of 0.00008726 listeriosis cases per year linked to the consumption of these RTE salads. Sensitivity analysis considering different time–temperature scenarios indicated a very low median risk per portion (<−7 log), even if the assessed RTE chicken salad was kept in abuse storage conditions.