The Bactericidal Efficacy and the Mechanism of Action of Slightly Acidic Electrolyzed Water on Listeria monocytogenes' Survival.

Huiying Li,Duo Liang,Jin Huang,Huan Rao,Chaojing Cui,Jianxiong Hao,Dandan Zhao

doi:10.3390/foods10112671

Abstract

In the present work, the bactericidal efficacy and mechanism of slightly acidic electrolyzed water (SAEW) on L. monocytogenes were evaluated. The results showed that the strains of L. monocytogenes were killed completely within 30 s by SAEW whose available chlorine concentration (ACC) was higher than 12 mg/L, and it was confirmed that ACC is the main factor affecting the disinfection efficacy of SAEW. Moreover, our results demonstrated that SAEW could destroy the cell membrane of L. monocytogenes, which was observed by SEM and FT-IR, thus resulting in the leakage of intracellular substances including electrolyte, protein and nucleic acid, and DNA damage. On the other hand, the results found that SAEW could disrupt the intracellular ROS balance of L. monocytogenes by inhibiting the antioxidant enzyme activity, thus promoting the death of L. monocytogenes. In conclusion, the bactericidal mechanism of SAEW on L. monocytogenes was explained from two aspects including the damage of the cell membrane and the breaking of ROS balance.

Highlights

Foodborne pathogens have been raising increasing concerns because they are associated with the outbreak of foodborne disease and present an extensive health burden worldwide
Considering that all of the types of slightly acidic electrolyzed water (SAEW) used in the present study have similar pH values but different available chlorine concentration (ACC), we confirm that ACC is the main factor affecting the disinfection efficacy of SAEW on L. monocytogenes, which is in agreement with the previous reports [29]
The results showed that SAEW had a good bactericidal effect on strains of L. monocytogenes, and ACC played an important role in the bactericidal efficacy

Summary

Introduction

Foodborne pathogens have been raising increasing concerns because they are associated with the outbreak of foodborne disease and present an extensive health burden worldwide. Listeria monocytogenes (L. monocytogenes) is one of the main foodborne pathogens threatening human health in refrigerated food and is responsible for Listeriosis in children, the elderly, pregnant women and immunocompromised populations [1]. Scientists found that the main harmful factors of L. monocytogenes included Listeria hemolysin O, phospholipase and some virulence proteins, and so on [6,7,8,9,10,11]. In order to reduce the microbial contamination caused by foodborne pathogens, especially L. monocytogenes, chlorine sanitizer such as sodium hypochlorite (NaClO) and chlorine dioxide (ClO2 ) have traditionally been recognized as possessing high disinfection efficacy in the food industry. As an alternative to the traditional chlorine sanitizer, the strong antibacterial effect of electrolyzed oxidizing water (EOW) has been recognized as and has shown a promising prospect in the food industry

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Conclusion