Modeling the fate of listeria monocytogenes and salmonella enterica on fresh whole and chopped wood ear and enoki mushrooms

Authors: FAY, MEGAN - Food And Drug Administration(FDA); SALAZAR, JOELLE - Food And Drug Administration(FDA); GEORGE, JOSEPHINA - Illinois Institute Of Technology; CHAVDA, NIRALI - Illinois Institute Of Technology; LINGAREDDYGARI, PRAVALIKA - Illinois Institute Of Technology; PATIL, GAYATRI - Illinois Institute Of Technology; Juneja, Vijay; INGRAM, DAVID - Food And Drug Administration(FDA)

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2023
Publication Date: 5/9/2023
Citation: Fay, M.L., Salazar, J.K., George, J., Chavda, N.J., Lingareddygari, P., Patil, G.R., Juneja, V.K., Ingram, D. 2023. Modeling the fate of listeria monocytogenes and salmonella enterica on fresh whole and chopped wood ear and enoki mushrooms. Journal of Food Protection. 114. https://doi.org/10.1016/j.fm.2023.104304.
DOI: https://doi.org/10.1016/j.fm.2023.104304

Interpretive Summary: The pathogens, Listeria monocytogenes and Salmonella enterica, continue to be of significant concern to the food industry. We quantified the survival and/or growth of the pathogens on both whole and chopped enoki and wood ear mushrooms during storage at different temperatures. The results suggest that enoki mushrooms are an environment more conducive to the proliferation of both tested pathogens at 25C. Data obtained contribute to our understanding on the fate of both L. monocytogenes and S. enterica on these two types of specialty mushrooms and will aid regulatory agencies in developing time and temperature control guidelines during processing, transportation, distribution and storage for these food commodities.

Technical Abstract: wo recent foodborne illness outbreaks linked to specialty mushrooms have occurred in the U.S., both representing novel pathogen-commodity pairings. Listeria monocytogenes and Salmonella enterica were linked to enoki and wood ear mushrooms, respectively. The aim of this study was therefore to examine the survival of both L. monocytogenes and S. enterica on raw whole and chopped enoki and wood ear mushrooms during storage at different temperatures. Fresh mushrooms were either left whole or chopped and subsequently inoculated with a cocktail of either S. enterica or rifampicin-resistant L. monocytogenes, resulting in an initial inoculation level of 3 log CFU/g. Mushroom samples were stored at 5, 10, or 25C for up to 7 d. During storage, the population levels of S. enterica or L. monocytogenes on the mushrooms were enumerated. Population data for each pathogen were fitted to the primary Baranyi model to estimate growth rates and the secondary Ratkowsky square root model was used to model the relationship of growth rates with temperature. Both L. monocytogenes and S. enterica survived on both mushroom types and preparations at all temperatures. No proliferation of either pathogen was observed on mushrooms stored at 5C. At 10C, moderate growth was observed for both pathogens on enoki mushrooms and for L. monocytogenes on wood ear mushrooms; no growth was observed for S. enterica on wood ear mushrooms. At 25C, both pathogens proliferated on both mushroom types with growth rates ranging from 0.43 to 3.27 log CFU/g/d at 25C, resulting in times to a 1 log CFU/g increase in only 2.32 d to 0.31 d (7.44 h). Secondary models were generated for L. monocytogenes on whole wood ear mushrooms and for S. enterica on whole enoki mushrooms with goodness-of-fit parameters of r2=0.09855/RMSE=0.0479 and r2=0.9882/RMSE=0.1417, respectively. Results from this study can aid in understanding the dynamics of L. monocytogenes and S. enterica on two types of specialty mushrooms.