Isolation and study on the technological and probiotic characterization of Lactobacilli in traditional white Lighvan cheese

Probiotics and especially Lactobacilli are among the most important components widely used in food technology. Isolation and characterization of indigenous probiotics should be performed in native populations. In order to isolate lactobacillus spp. from Iranian traditional Lighvan cheese to be used as starters, 15 cheese samples were randomly selected and tested for technological and probiotics properties. Lactobacilli were characterized using culture-based and bio-chemical techniques and results were verified using PCR analyses of the 16S rRNA region. The probiotic characteristics of these bacteria were studied by acid and bile tolerance. The susceptibility of different isolates against a number of important antibiotics was tested. The technological traits of LAB were assessed using measurement of acid production and analyzing salt tolerance. The isolates were also screened for proteolytic and lipolytic activity. Of the 12 samples containing Lactobacilli, 10 belonged to L. plantarum while 2 were close to L. bulgaricus spp. All isolates were tolerant to 3% NaCl and 9 tolerated 6-8% NaCl. Almost all isolates were lipase-positive at 37 °C and 30 °C. Nine Lactobacilli were shown to be protease-positive at 37°C. Two isolates were completely tolerant to pH 1.55, 4 had intermediate resistance, 4 were of weak resistance and 1 was sensitive. All but one isolate were tolerant to 0.03% bile acid. Some isolates were shown to be sensitive to erythromycin, ampicillin, tetracycline, amikacin and rifampicin. Results indicate that most of the isolated Lactobacilli can be used as industrial cheese starters and/or as native probiotics in production of functional foods.