Identification and Characterization of Lactococcus lactis ssp.lactis Isolated from Raw Milk and Milk Products of Turkey and Iran

Abstract

Lactococcus lactis ssp.lactis strains are the best known and characterized species of lactic acid bacteria which plays an important role as starter cultures in industrial dairy fermentation, owing to its pH lowering effect, production of antimicrobial metabolites and enhancement of the organoleptic attributes. The objective of this study was to identify and evaluate the varied properties of the natural L.lactis ssp.lactis strains from raw milk and dairy products obtained from different provinces of Turkey and Iran during the period of April to June 2016. Out of 262 dairy samples, L.lactis ssp.lactis were isolated from 98 samples. In order to evaluate the obtained strain as a good quality starter culture, litmus milk reaction, total titratable acidity, skim milk agar, antimicrobial activity and antibiotic resistance tests were conducted. The genetic basis of the observed phenotypic resistance obtained by disc diffusion test was further confirmed by PCR. Lactic acid production by Iranian cheese samples were significantly higher than Turkish samples (p 0.05). Iranian cheese isolates showed higher antimicrobial activity againts E. faecalis and E. coli as compared to Turkish isolates. (p 0.05). However, tetracycline and streptomycin resistance gene was only confirmed by PCR in Turkish cheese samples. Emphasis must be given to selection of the milk source for obtaining good quality starter cultures.  Further studies may be conducted to learn the effect of ecological parameters on bacterial strains.