Abstract

Most of the probiotic products undergo industrial processing involving high temperatures. Thermotolerance of probiotic microorganisms used in such processing is important to make it effective during consumption or administration. Very few studies have been devoted to the thermotolerance of probiotics. This work aimed at assessing the thermotolerance and probiotic potential of lactic acid bacteria isolated from “Gari” produced in the South West Region of Cameroon. Lactic acid bacteria were isolated from “Gari” samples using pour plate method on De Man Rogosa and Sharpe (MRS) agar. The catalase negative colonies were selected and subjected to thermotolerance test by heating the cells suspended in MRS broth at temperatures ranged from 50-60 °C for 1h and measurement of their growth at 30 °C by spectrophotometry. Only two isolates (SB1 and SB2) were able to tolerate heating treatment at 50-56°C and were selected. They were respectively identified using API 50 CHL BioMerieux kit as strain of Lactobacillus plantarum and Lactobacillus acidophilus. These selected strains showed high inhibitory activity against important food borne pathogenic bacteria such as Salmonella enterica serovar Enteritidis, Salmonella enterica serovar Typhimurium, Esherichia coli, Satphylococcus aureus and a food spoilage microorganism; Listeria monocytogenes with an average inhibition diameter greater than 15 mm. The selected probiotic lactic acid bacteria also tolerate pH3.0 and 0.3 % (v/v) oxgall-bile. Owing to their properties they may be used in industrial processing of probiotic products.

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