Growth Potential of Listeria monocytogenes in Three Different Salmon Products.

Corinne Eicher,Arnulf Meusburger,Claudia Guldimann,Roger Stephan,Andres Ruiz Subira,Sabrina Corti

doi:10.3390/foods9081048

Corinne Eicher, Arnulf Meusburger + Show 4 more

Open Access

https://doi.org/10.3390/foods9081048

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Journal: Foods (Basel, Switzerland)	Publication Date: Aug 3, 2020
Citations: 9	License type: CC BY 4.0

Affiliation: University of Zurich

Abstract

Cold smoked salmon and sushi salmon have been implicated in outbreaks of listeriosis. We performed challenge tests and a durability study with Listeria monocytogenes on different salmon products to determine the growth potential of this important food-borne pathogen. Data from the challenge test showed a significant growth potential of L. monocytogenes on all of the tested salmon products, with faster growth in sushi salmon than in cold smoked salmon. In identical products that were naturally contaminated at low levels, the durability study did not confirm a high growth potential, possibly due to interactions with competing microflora. The injection of sodium lactate (NaL) at a high concentration (30%) into cold smoked salmon significantly reduced the growth potential of L. monocytogenes. In addition to good manufacturing practices, the injection of higher concentrations of NaL may therefore be a useful additional hurdle to prevent growth of L. monocytogenes to high numbers in the tested salmon products.

Highlights

Listeria monocytogenes is the causative agent of listeriosis
The results from this study add to the evidence that salmon is a high-risk product for growth of L. monocytogenes
Even at the storage temperature of 5 ◦ C, the growth potential exceeded 0.5 log CFU/g and put the product in the category “able to support the growth of L. monocytogenes”

Summary

Introduction

Listeria monocytogenes is the causative agent of listeriosis. In particular the elderly, pregnant and immunosuppressed people are at increased risk for listeriosis [1]. Listeria monocytogenes is able to grow in high salt concentrations (7–9% wt/vol) [4], at cold storage temperatures (4 ◦ C) [2,5], and to survive under the selective pressure of commonly used disinfectants such as benzalkonium chloride and peracetic acid [6]. These properties make L. monocytogenes prone to persist in food production facilities. The complex task of keeping food production environments free of L. monocytogenes combined with the severity of the disease with mortality rates between

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