Molecular identification and characterization of lactic acid producing bacterial strains isolated from raw and traditionally processed foods of Punjab, Pakistan

Abstract

Seventeen (17) wild strains of lactic acid producing bacteria (LAB) were screened, out of one hundred and forty-four (144) bacterial strains isolated from different local food groups, on the basis of stress tolerance assays. Identification of the screened strains was further confirmed by 16S ribosomal DNA sequences and strain level differentiation was carried out by sugar fermentation tests. These strains were further analyzed for their ability to produce lactic acid. Overall, Leuconostoc mesenteroides was found as pre-dominant group (41.1% prevalence) among LAB strains in the isolated food samples. Some opportunistic pathogens were also isolated from these media. Among the tested strains maximum amount of lactic acid (26.457 mg/mL) was produced by the lactobacilli after 48 h growth in skim milk broth, while the least (12.131 mg/mL) was produced by pediococci. These LAB strains are being studied for their probiotic properties and good quality indigenous starter cultures from them are anticipated to be employed in food industry.