Lactobacillus Species from Iranian Jug Cheese: Identification and Selection of Probiotic Based on Safety and Functional Properties

Abstract

Background and Objective: Traditional fermented products are appropriate sources for the isolation of indigenous bacteria with probiotic characteristics and potential similar or better than commercial probiotics. In this study, Lactobacillus species were isolated from jug cheese, a type of Iranian traditional cheese, and their potential probiotic characteristics were studied. Material and Methods: Study of the probiotic species included hemolytic activity, antibiotic susceptibility, inhibitory activity against pathogenic bacteria, low pH and bile salts tolerance, viability in gastrointestinal tract conditions and adhesion ability to HT-29 cells. Results and Conclusion: Results showed that the isolates included no hemolytic activity and were susceptible or intermediate susceptibility to most antibiotics. Of four isolates, Lacto-bacillus plantarum KMJC4 showed the strongest antibacterial activity (MIC = 6.25 mg ml-1) against Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus and Salmonella enterica subsp. enterica serovar Typhimurium. All the isolates, except Lactobacillus curvatus KMJC3, preserved their viability after transition through the simulated gastrointestinal tract conditions above 106 CFU ml-1. Lactobacillus acidipiscis KMJC2 and Lactobacillus plantarum KMJC4 showed the lowest and the highest adhesion rates to HT-29 cells with 3.55 and 6.80 Log10 CFU ml-1 (42.51 and 71.35%), respectively. Lactobacillus plantarum KMJC4 included a better bacterial inhibitory activity and adhesion to HT-29 cells than that Lactobacillus rhamnosus GG did as control. Lactobacillus brevis KMJC1 demonstrated appropriate probiotic characteristics such as antibacterial activity, viability in low pH, bile salts and gastrointestinal tract conditions and adhesion capability to HT-29 cells. In conclusion, Lactobacillus plantarum KMJC4 and Lactobacillus brevis KMJC1 were introduced as probiotic capable strains. Based on the results from the current in vitro study, finding probiotics with similar or better characteristics than commercial probiotics within indigenous bacteria is quite possible. In vivo assessment of the bacteria can be considered in future studies, investigating using possibilities of these bacteria in food industries to produce functional fermented foods and in pharmaceutical industries in form of probiotic capsules. Conflict of interest: The authors declare no conflict of interest