Bioprotective potential of lactic acid bacteria for Salmonella biocontrol in vitro

Abstract

Lactic acid bacteria (LAB) are an important option for Salmonella control in animal production, resulting in lower use of therapeutic and zootechnical antibiotics. The objective of this research was to isolate LAB for in vitro verification of their bioprotective potential. 11 bacteria were identified as Pediococcus acidilactici, two as Lacticaseibacillus (Lactobacillus) rhamnosus, one as Lacticaseibacillus (Lactobacillus) paracasei paracasei, one as Limosilactobacillus fermentum, and one as a consortium of Lactobacillus delbrueckii bulgaricus and L. fermentum. All bacteria showed effectiveness against Salmonella, with emphasis on the inhibition halos of P. acidilactici PUCPR 011 against Salmonella Enteritidis 33SUSUP, S. Enteritidis 9SUSP, S. Enteritidis 56301, S. Enteritidis CRIFS 1016, Salmonella Typhimurium ATCC™ 14028®, and Salmonella Gallinarum AL 1138, with inhibition of 7.3 ± 0.5 mm, 7.7 ± 1.0 mm, 9.0 ± 1.8 mm, 7.3 ± 0.5 mm, 7.7 ± 1.0 mm, and 7.3 ± 0.5, respectively. The isolates P. acidilactici PUCPR 011, P. acidilactici PUCPR 012, P. acidilactici PUCPR 014, L. fermentum PUCPR 005, L. paracasei paracasei PUCPR 013, and L. rhamnosus PUCPR 010 showed inhibition greater than 2 mm against at least 3 Salmonella strains, and were used for encapsulation and in vitro digestion. The encapsulation efficiency ranged from 76.89 ± 1.54 to 116.48 ± 2.23%, and the population after 12 months of storage was from 5.31 ± 0.17 to 9.46 ± 0.09 log CFU/g. When simulating swine and chicken digestion, there was a large reduction in bacterial viability, stabilizing at concentrations close to 2.5 log CFU/mL after the analyses. The analyzed bacteria showed great potential in vitro for application as bioprotectors, and further analyses are required to determine their in vivo effectiveness.