Molecular identification and evaluation of antimicrobial effects of dominant LAB isolated from Tarkhineh and its bacteriocin-like substances on some foodborne microorganisms

Subject Areas : Food Microbial Contamination

Atena Sarani ¹ , علیرضا صادقی ² , Morteza Khomeiri ³ , Yahya Maghsoudlou ⁴ , Ali Moayedi ⁵ , Maryam Ebrahimi ⁶

1 - MSc student of Food Biotechnology, College of Food Technology, Gorgan University of Agricultural Sciences and Natural Resources
2 - عضو هیات علمی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، دانشکده صنایع غذایی
3 - Faculty member
4 - Faculty member
5 - Faculty member
6 - Health research center of food, drug and natural products, Golestan University of Medical Science, Gorgan, Iran.

Received: 2018-11-18 Accepted : 2019-06-11 Published : 2019-09-23

Keywords: antimicrobial effect, LAB isolate, Tarkhineh, Bacteriocin-like substances,

Abstract :

Isolation and evaluation of the characteristics of lactic acid bacteria (LAB) from traditional fermented products have always the possibility of exposure to isolates with unique capabilities.In the present study after molecular identification of dominant LAB isolated from Tarkhineh, antibacterial and antifungal effects of the isolate and its bacteriocin-like substances on some foodborne indicators were investigated in accordance with the reference methods. Sequencing results of polymerase chain reaction led to the identification of Lactococcus lactis as dominant isolate. LAB isolate had proper antibacterial effect but there was no significant difference (P<0.05) between growth inhibitory diameter of S. aureus and E. coli in present of the isolate. Furthermore, the inhibitory effect of the crude supernatant was higher than that of the neutralized and treated supernatants against studied indicator bacteria. The highest reduction in the population of S. aureus (87.91%) was also observed in the presence of crude supernatant obtained from Logarithmic growth phase. The LAB isolate had the higher antifungal effect on A. flavus rather than A. niger, but the growth rate of A. niger compared to A. flavus was remarkably (P<0.05) higher in each of the third to sixth days of incubation in the presence of bacteriocin-like substances. Based on the results of this study, Lactococcus lactis isolate and its bacteriocin-like substrates can be used as starter culture in fermented food processing, or as bio-preservative in food and pharmaceutical industries.