Multi-Functional Potential of Lactic Acid Bacteria Strains and Antimicrobial Effects in Minimally Processed Pomegranate (Punica granatum L. cv Jolly Red) Arils

Abstract

This study aimed to evaluate the antimicrobial activity of both cells, and cell-free supernatants (CFS) of 7 selected lactic acid bacteria (LAB) strains belonging to Limosilactobacillus fermentum (4 strains), Lacticaseibacillus paracasei (1 strain), Lacticaseibacillus rhamnosus (1 strain), and Enterococcus faecium (1 strain) species, against Listeria monocytogenes, Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa and Staphylococcus aureus, by both the agar-well diffusion and co-culture methods. In addition, probiotic and safety traits were also detected. Great variability was detected on antimicrobial effects, whereas all tested strains were found sensitive to most of the tested antibiotics, and without any DNase, gelatinase, or hemolytic activity. Moreover, strains showed excellent survival in acidic conditions and exhibited tolerance to pepsin and bile salts. Based on the in vitro results, the CFSs of two selected L. fermentum strains were applied, in a mixed solution, as bio-preservative into minimally processed pomegranate arils, inoculated with a cocktail of L. monocytogenes and E. coli. Samples, packaged in an ordinary atmosphere, were analyzed during refrigerated storage, for up to 12 days, for physicochemical (as weight loss, texture, color, pH, total soluble solids and organic acid content) and for microbiological traits. Results revealed the effectiveness of CFS, up to 12 days, in reducing weight loss and microbial growth, without any significant effect on texture, total soluble solid content and color, found comparable to the acid citric treatment, highlighting the multi-functional potential of selected probiotic strains.

Isolation and Identification of Chicken-Derived Lactic Acid Bacteria: In Vitro Probiotic Properties and Antagonistic Effects against Salmonella pullorum, Staphylococcus aureus, and Escherichia coli

“…Co-culturing probiotics and pathogens is an effective method to evaluate the inhibitory ability of the former against the latter. Ben and his colleagues found that L. rhamnosus LBF 16 and L. paracasei LBF 19 exhibited the complete inhibition of E. coli when co-cultured [52]. Wang et al [53] reported that L. plantarum completely inhibited the growth of enterotoxigenic E. coli after 24 h of co-culturing.…”

The Impacts of Acidophilic Lactic Acid Bacteria on Food and Human Health: A Review of the Current Knowledge

“…On the contrary, Sakoui et al (2022) reported that strains of Enterococcus genus (Enterococcus faecium V6-112, Enterococcus faecalis JM102, Enterococcus mundtii MAV6B, Enterococcus gallinarum HBUAS52471, Enterococcus casseflavus APHG2) did not show gelatinase activity [21]. Ben Farhat et al (2022) also did not observe gelatinase activity in any of the LAB strains of Limosilactobacillus fermentum (4 strains), Lacticaseibacillus paracasei (1 strain), Lacticaseibacillus rhamnosus (1 strain) [162]. In another study, it was revealed that strains belonging to the Lactiplantibacillus plantarum and Enterococcus faecalis groups did not show gelatinase activities [158].…”

One Health Perspectives on Food Safety in Minimally Processed Vegetables and Fruits: From Farm to Fork

“…This leads consumers to prefer foods that are not only healthy and easy to prepare [6][7][8][9][10] but also of high quality and safety, preferably without additives [7,9,11]. A wide range of ready-to-eat, refrigerated food products with longer shelf lives is available to meet these preferences [10][11][12][13][14]. Among these, a specific category of products known as minimally processed foods (MP) [7,15,16] has emerged.…”