Antimicrobial Activity of Pediococcus Acidilactici PTCC 1954 and Leuconostoc Mesenteroides PTCC 1953 strains Isolated from Organic Meat Sausages

Organic meat products are well known for their probiotic values due to the presence of probiotic lactic acid bacteria such as Lactobacillus, Leuconostoc, Lactococcus, and Pediococcus strains. The present study aimed to isolate and characterize new strains of lactic acid bacteria (LABs) from organic meat sausages and evaluate their antimicrobial activities.

In this study, LAB strains were isolated from vacuum-packed organic meat sausages bought from Solico Group Co Ltd. (Tehran, Iran). All isolates were characterized by morphological, biochemical, and 16S rRNA analysis. The primary antibacterial activity of the isolates was evaluated against Micrococcus luteus PTCC 1408. The growth kinetics and antimicrobial activity of the strain MN-B against Lactobacillus casei ATCC 39392 were determined in an MRS broth medium. In addition, a bacteriocin produced by the strains MN-B revealed antimicrobial activity against selected foodborne pathogens. Bacteriocin produced by the MN-B strain was partially purified using the adsorption-desorption method followed by dialyzes.

In this study, two Pediococcus spp. and three Leuconostoc spp. with antimicrobial activity were isolated from vacuum-packed organic meat sausages and designated as MN-A, MN-B, MN-A2, MN-A2-1, and MN-A3. The results showed that the isolate MN-A and MN-B belonged to the strain Pediococcus acidilactici and the MN-A2, MN-A2-1, and MN-A3 isolates were identified as Leuconostoc mesenteroides strains. Amongst the isolates, the strain MN-B showed the highest antimicrobial activity against the Micrococcus luteus PTCC 1408. The molecular weight of bacteriocin was about 5.0 KDa.

Pediococcus acidilactici (strain MN-B) showed significant antimicrobial activity against Salmonella enterica subsp. enterica serotype Typhimurium PTCC 1709, Staphylococcus aureus PTCC 1113, Listeria monocytogenes PTCC1302, and Listeria inovani PTCC 1303. Therefore, this strain can be considered a potential candidate in different sectors such as the food industry as a preservative.