CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIA ISOLATED FROM SHIMPIA AGAINST SELECTED PATHOGENIC MICROORGANISMS

Abstract

Traditional dairy products are food products prepared by traditional knowledge of source community. They can have different physicho-chemical and microbiological properties based on the milk source, way of processing and agro-ecological factors. The aim of this study was to evaluating physico-chemical and microbiological quality of shimpia and characterization and testing the antibacterial potential of lactic acid bacteria isolates from Shimpia in the selected districts of Wolayta zone, southern Ethiopia. In line with this, a traditional fermented milk product produced among the Wolayta community called Shimpia was studied. The study was conducted in three selected agro-ecologically different kebeles. Thus, for the questionnaire based survey study, a total of 162 farmers with Kokatemarachere (79), Bossakecha (45) and Gulgula (38) were participated. Additionally, 10 Shimpia sample from each kebele with a total of 30 samples were collected to determine the physicho-chemical and microbial analysis using standard procedures. Besides, the antimicrobial activities of LAB isolates from Shimpia were tested against selected pathogens using disc diffusion assay. The results showed 57.9% of respondents produced Shimpia from milk sourced from local breed cows. The majority (64.8%) of the respondents used tap water for cleaning of equipments used for Shimpia production. Nearly half of (52.5%) the respondents used locally available herbs as cleaning agent. The pH of Shimpia prepared at farmers house ranged from 4.5 to 4.7 with average constituents of total solid 11.7%, fat 4.5%, protein 3.1%, lactose 3.7% and ash 0.7%. The total solid and fat content of the samples were significantly different across the agro-ecological locations (P< 0.05). In addition, enumeration of microorganisms (cfu/g) showed that total aerobic bacteria count (8.79±0.04), yeast and mould count (6.49±0.05), total lactic acid bacteria, (4.77±0.01), and total Coliform count (4.22±0.03). A total of 72 strains of LAB belonging to Lactobacillus, Streptococcus, Pediococcus, Leuconostoc, Lactococus and Entrococus species were isolated and its antimicrobial activities was tested against Salmonella typhi, Listeria monocytogenes, S,aurious (ATCC-25923) and E.coli O157:H7(ATCC-25922). However, only 8 strains of LAB showed antagonistic effect against pathogens with inhibition zone ranged from 9.0mm to 11.8mm. The isolates’ antagonism effect against different pathogens was significantly different at P < 0.05.