Listeria monocytogenes in Milk: Occurrence and Recent Advances in Methods for Inactivation

Sarah Lee,Celso Balthazar,Carlos de Oliveira,Larissa Franco,Ramon Rocha,Carlos Corassin,Adriano da Cruz,Jonas Guimarães,Leandro Cappato

doi:10.3390/beverages5010014

Abstract

Milk is one of the most important food items consumed by humans worldwide. In addition to its nutritional importance, milk is an excellent culture medium for microorganisms, which may include pathogens such as Listeria monocytogenes (L. monocytogenes). Traditional processing of milk for direct consumption is based on thermal treatments that efficiently eliminate pathogens, including pasteurization or sterilization. However, the occurrence of L. monocytogenes in milk as a consequence of failures in the pasteurization process or postpasteurization contamination is still a matter of concern. In recent years, consumer demand for minimally processed milk has increased due to the perception of better sensory and nutritional qualities of the products. This review deals with the occurrence of L. monocytogenes in milk in the last 10 years, including regulatory aspects, and recent advances in technologies for the inactivation of this pathogen in milk. The results from studies on nonthermal technologies, such as high hydrostatic pressure, pulsed electric fields, ultrasounds, and ultraviolet irradiation, are discussed, considering their potential application in milk processing plants.

Highlights

Milk is the fluid secreted by mammals for the nourishment of their offspring [1]
The findings presented showed similar bacterial inactivation when US-treated milk was compared to conventional pasteurization, with the advantage of using small temperature processing
The occurrence of L. monocytogenes is worldwide, and emerging technologies can be used for its inactivation and to guarantee the safety of processed products

Summary

Introduction

Milk is the fluid secreted by mammals for the nourishment of their offspring [1]. Since humans began to domesticate lactating animals, milk and milk products have been part of the human diet [2].Milk is considered one of the most complete sources of nutrients for human beings because of its diverse components, such as proteins, vitamins, and minerals that are important in human nutrition [3,4].due to its high nutritional value, neutral pH, and high water activity, raw milk serves as an excellent growth medium for different microorganisms, whose multiplication depends mainly on temperature and on competing microorganisms and their metabolic products [5]. Milk is the fluid secreted by mammals for the nourishment of their offspring [1]. Since humans began to domesticate lactating animals, milk and milk products have been part of the human diet [2]. Milk is considered one of the most complete sources of nutrients for human beings because of its diverse components, such as proteins, vitamins, and minerals that are important in human nutrition [3,4]. Due to its high nutritional value, neutral pH, and high water activity, raw milk serves as an excellent growth medium for different microorganisms, whose multiplication depends mainly on temperature and on competing microorganisms and their metabolic products [5]. Raw milk creates good growth conditions for a variety of spoilage and potentially pathogenic microorganisms, such as. Shiga toxin-producing Escherichia coli (STEC), Listeria monocytogenes (L. monocytogenes), Salmonella enterica, Campylobacter spp., Yersinia spp., and others [6,7].

Objectives

Findings

Conclusion