Probiotic potential of autochthone microbiota from dry-rippened sheep ham

Abstract

This study assessed the potential of probiotic characteristics of bacterial strains isolated from dry-cured sheep ham. It is one of the most common autochthonous processed meat products made in a traditional way on the Pešter plateau (Western Serbia). Isolates were identified as Lactobacillus curvatus (9 strains), Lactobacillus sakei (3 strains), and Enterococcus faecium (4 strains) using MALDI-TOF mass spectrophotometry. The study of probiotic characteristics of 16 dry-cured sheep ham isolates included survival rate through the gastrointestinal tract (GI), the possibility of biogenic amine synthesis, growth on medium with different concentrations of phenol,and antimicrobial activity. The results showed that in simulated gastric juice conditions, the cell number decreased after the first hour of incubation in the tested strains of Lb. curvatus, Lb. sakei and En. faecium except in the case of Lb. curvatus IIos19 where the number of cells remained approximately the same. After the second hour of incubation, the number of cells generally remained at the level of the first hour except in the case of the following isolates: Lb. sakei Ios12, Lb. curvatus IIos18 and En. faecium IIos24, where an increase in the number of cells was noticed after the second hour of incubation. In simulated small intestine conditions, an increase in the number of vital cells after 4 and 6 hours of incubation was observed in the isolates Lb. curvatus IIos4, Lb. sakei (Ios12, IIIos13), and En. faecium Ios1a. Synthesis of biogenic amines was not observed in investigated lactobacilli and enterococci. Analyzed isolates exhibited growth on media with 0.1% and 0.2% phenol, while 5 isolates exhibited decarboxylase activity. Six Lactobacillus strains, Lb. curvatus (IIos6, IIos17, and IIIos1), Lb. sakei (IIIos16, Ios12, and IIIos13) and En. faecium Ios4 inhibited the growth of tested pathogens, including Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 19115, Pseudomonas aeruginosa ATCC 27853 and Bacillus cereus ATCC 14579.