Changes in antagonistic activity of lactic acid bacteria induced by their response to technological factors

Dovile Jonkuviene,Irena Mačionienė,Jūratė Stankienė,Joana Šalomskienė,Jūratė Repečkienė,Lina Vaičiulytė-Funk,Asta Abraitienė

doi:10.23986/afsci.50936

Abstract

This study examined the changes in antagonistic activity of selected lactic acid bacteria (LAB) in response to technological factors used in food production. The antimicrobial activity of 12 selected LAB strains was assessed against the bacterial and fungal strains using the agar well diffusion method. Sodium chloride (NaCl) 6.5–8.0%, glucose 20-30% and pH 4.0, pH 8.0 and higher were the most crucial factors in reducing the spectra of the microorganisms antagonized. Heating at 80 °C or 100 °C had a greater negative impact than 63 °C on the antifungal activity of LAB. Freezing at –72 °C eliminated the antifungal activity, or it changed from fungicidal to fungistatic. Although each LAB demonstrated the ability to retain antimicrobial activity induced by various technological factors, Lactococcus lactis 768/5 was superior in retaining high antimicrobial activity against tested indicator strains.

Highlights

Lactic acid bacteria (LAB) have been studied very intensively for their potential use as safe and natural food preservatives
This study focuses on twelve lactic acid bacteria (LAB) strains indicated by the possession of enhanced antimicrobial activity by the largest zones of inhibition (ZOI), or some ZOI induced by catalase-treated neutralisates (Table 1)
Tested lactic acid bacteria cultures demonstrated a strong antimicrobial activity mostly specialised against one indicator species during treatment of technological factors

Summary

Introduction

Lactic acid bacteria (LAB) have been studied very intensively for their potential use as safe and natural food preservatives. Many studies focused on the antibacterial activity of LAB while less research has been done concerning the antifungal effect of LAB strains. A few studies have dealt with both the antibacterial and antifungal activities of the same LAB strains in complex (Çakir 2010, Smaoui et al 2010, Stoyanova et al 2010, Šalomskienė et al 2014). Abundant screenings of novel LAB strains with improved antagonistic activity were carried out under the very close to optimal chemical environment. In reality, the growth of LAB may be confronted by lots of changes in the chemical environment because of the wide range of possible media compositions in vivo.

Methods

Results

Discussion

Conclusion