Effect of UV-C Irradiation and Lactic Acid Application on the Inactivation of Listeria monocytogenes and Lactic Acid Bacteria in Vacuum-Packaged Beef.

Giannina Brugnini,Jesica Rodríguez,Soledad Rodríguez,Caterina Rufo

doi:10.3390/foods10061217

Giannina Brugnini, Jesica Rodríguez + Show 2 more

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https://doi.org/10.3390/foods10061217

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Journal: Foods (Basel, Switzerland)	Publication Date: May 28, 2021
Citations: 8	License type: CC BY 4.0

Affiliation: Universidad de la República

Abstract

The objective of this study was to test the effect of the combined application of lactic acid (0–5%) (LA) and UV-C light (0–330 mJ/cm2) to reduce Listeria monocytogenes and lactic acid bacteria (LAB) on beef without major meat color (L *, a *, b *) change and its impact over time. A two-factor central composite design with five central points and response surface methodology (RSM) were used to optimize LA concentration and UV-C dose using 21 meat pieces (10 g) inoculated with L. monocytogenes (LM100A1). The optimal conditions were analyzed over 8 weeks. A quadratic model was obtained that predicted the L. monocytogenes log reduction in vacuum-packed beef treated with LA and UV-C. The maximum log reduction for L. monocytogenes (1.55 ± 0.41 log CFU/g) and LAB (1.55 ± 1.15 log CFU/g) with minimal impact on meat color was achieved with 2.6% LA and 330 mJ/cm2 UV-C. These conditions impaired L. monocytogenes growth and delayed LAB growth by 2 weeks in vacuum-packed meat samples throughout 8 weeks at 4 °C. This strategy might contribute to improving the safety and shelf life of vacuum-packed beef with a low impact on meat color.

Highlights

Listeria monocytogenes is a human pathogen that may cause listeriosis, a foodborne infection with a low morbidity and a high mortality rate (20–30%) [1]
The present study shows for the first time the effect of the combined application of lactic acid (LA) and UV-C on L. monocytogenes and lactic acid bacteria (LAB) in vacuum-packed beef
The major findings of the present study were: (i) the quadratic model obtained allowed us to predict L. monocytogenes log reduction in vacuum-packed beef treated with LA and UVC, (ii) the maximum log reduction for both L. monocytogenes (1.55 ± 0.41 log CFU/g) and LAB (1.55 ± 1.15 log CFU/g) with minimal impact on meat color was achieved with the application of 2.6% LA and 330 mJ/cm2 UV-C, and (iii) under these conditions, there was no increase in L. monocytogenes counts over 8 weeks of storage at 4 ◦ C, and LAB growth was delayed by 2 weeks compared to control samples

Summary

Introduction

Listeria monocytogenes is a human pathogen that may cause listeriosis, a foodborne infection with a low morbidity and a high mortality rate (20–30%) [1]. L. monocytogenes in raw meat does not cause major public health problems since meat is generally consumed after cooking at temperatures above 70 ◦ C. Contaminated raw meat when used as raw material for food products that in their production process fail to eliminate the pathogen may present a safety risk [1]. Contamination of meat with Listeria monocytogenes is a consequence of the production process [2]. L. monocytogenes can survive and grow in vacuum-packed meat cuts stored at temperatures between 0 and 4 ◦ C; different strategies are applied in abattoirs to minimize bacterial contamination [3,4]. Lactic acid (LA) application is accepted because it does not present risks to consumer health.

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