Screening of Lactic Acid Bacteria for the Bio-Control of Botrytis cinerea and the Potential of Lactiplantibacillus plantarum for Eco-Friendly Preservation of Fresh-Cut Kiwifruit.

Nicola De Simone,Giuseppe Spano,Maria Lucia Valeria De Chiara,Vittorio Capozzi,Giancarlo Colelli,Pasquale Russo,Samira Brahimi,Djamel Drider,Maria Luisa Amodio

doi:10.3390/microorganisms9040773

Abstract

Botrytis cinerea, responsible for grey mold, represents the first biological cause of fruit and vegetable spoilage phenomena in post-harvest. Kiwifruit is a climacteric fruit particularly prone to this mold infestation during storage. Lactic acid bacteria (LAB) are food-grade bacteria that can synthesize several metabolites with antimicrobial activity and are, therefore, suggested as promising and eco-friendly resources for the bio-control of molds on fruits and vegetables. In this work, we propose the screening of a collection of 300 LAB previously isolated from traditional sourdoughs for their ability to counteract in vitro the growth of Botrytis cinerea CECT 20973. Only 2% of tested LAB strains belonging to Lactiplantibacillus plantarum species, exerted a strong antagonism against B. cinerea. The cell-free supernatants were partially characterized and results clearly indicated that high levels of lactic acid contributed to the antagonistic activity. PAN01 and UFG 121 cell-free supernatants were investigated as potential bio-control agents in a preliminary in vivo assay using freshly cut kiwifruits as a food model. The application of cell-free supernatants allowed to delay the growth of B. cinerea on artificially contaminated kiwifruits until two weeks. The antagonistic activity was greatly affected by the storage temperature (25 °C and 4 °C) selected for the processed fruits, suggesting the importance to include microbial-based solution in a broader framework of hurdle technologies.

Highlights

Consumers highly appreciate kiwifruit for its sour and sweet taste, and for its associated healthy features, attributed to high levels of vitamin C, flavonoids, minerals, and significant amounts of chlorophyll and carotenoids
We investigated the effectiveness of 300 Lactic acid bacteria (LAB) strains isolated from traditional sourdoughs to contrast B. cinerea, a specific and diffused spoilage microbe of fruits and vegetables
98% of the tested LAB strains were barely able to inhibit B. cinerea CECT 20973, while only six strains (2%) exerted a strong antagonism, showing an inhibition halo higher than 10 mm

Summary

Introduction

Consumers highly appreciate kiwifruit for its sour and sweet taste, and for its associated healthy features, attributed to high levels of vitamin C, flavonoids, minerals, and significant amounts of chlorophyll and carotenoids. As part of a balanced diet, has been reported to have multiple benefits (other than the nutritional ones), such as antioxidant capacity [1], an increase of HDL cholesterol and decrease of triglycerides [2], protection from oxidative stress [3], and favorable changes in the human colonic microbial community [4]. It is a crop with high economic relevance, with about four million tons produced worldwide in 2017, and approximately 1.5 million tons exported among countries [5]. Recommended conditions include storage temperature of 0 ◦ C, relative humidity higher than 90% and atmosphere modification with 1 to 2% O2 and 3 to

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