Modeling Salmonella Typhimurium Inactivation in Dry-Fermented Sausages: Previous Habituation in the Food Matrix Undermines UV-C Decontamination Efficacy.

Yhan S Mutz,Vania M F Paschoalin,Denes K A Rosario,Carlos A Conte-Junior,Patricia C Bernardes

doi:10.3389/fmicb.2020.00591

Yhan S Mutz, Vania M F Paschoalin + Show 3 more

Open Access

https://doi.org/10.3389/fmicb.2020.00591

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Abstract

The effects of previous Salmonella Typhimurium habituation to an Italian-style salami concerning pathogen resistance against ultraviolet-C light (UV-C) treatment were modeled in order to establish treatment feasibility for the decontamination of dry-fermented sausage. S. Typhimurium following 24 h habituation in fermented sausage (habituated cells) or non-habituation (non-habituated cells) were exposed to increasing UV-C radiation treatment times. The Weibull model was the best fit for describing S. Typhimurium UV-C inactivation. Heterogeneity in UV-C treatment susceptibilities within the S. Typhimurium population was observed, revealing intrinsic persistence in a sub-population. UV-C radiation up to 1.50 J/cm2 was a feasible treatment for dry-fermented sausage decontamination, as the matrices retained instrumental color and lipid oxidation physiochemical characteristics. However, habituation in the sausage matrix led to a 14-fold increase in the UV-C dose required to achieve the first logarithm reduction (δ value) in S. Typhimurium population. The results indicate that, although UV-C radiation might be considered an efficient method for dry-fermented sausage decontamination, effective doses should be reconsidered in order to reach desirable food safety parameters while preserving matrix quality.

Highlights

Ready-to-eat meat products may pose a safety risk for consumers, due to contamination by foodborne pathogens, such as Salmonella, during either the pre or post-processing stages (Mutz et al, 2019, 2020)
As no specific step is included along the manufacturing process of dry-fermented meat products for pathogen elimination, the abiotic stresses exerted by the food matrix can transform pre-existent foodborne pathogens into more persistent and even more virulent organisms (Mutz et al, 2020)
L* luminosity; a* redness; E total color difference when compared to untreated samples; thiobarbituric acidreactive substance (TBARS) is expressed as mg of MDA/kg; Different letters in the same column indicate differences (p < 0.05)

Summary

Introduction

Ready-to-eat meat products may pose a safety risk for consumers, due to contamination by foodborne pathogens, such as Salmonella, during either the pre or post-processing stages (Mutz et al, 2019, 2020). Salmonella Typhimurium is the most frequent serovar concerning animalbased food contamination (Ferrari et al, 2019) and the second serovar involved in outbreaks (Gossner et al, 2012; Scavia et al, 2013; Andreoli et al, 2017). Physicochemical matrix characteristics such as low water activity, a moderately acidic pH and indigenous competitive microbial population inherent to dry-fermented sausages are natural hurdles for microbial growth (Leistner and Gorris, 1995). As no specific step is included along the manufacturing process of dry-fermented meat products for pathogen elimination, the abiotic stresses exerted by the food matrix can transform pre-existent foodborne pathogens into more persistent and even more virulent organisms (Mutz et al, 2020)

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