Isolation of probiotic bacteria from raw camel's milk and their antagonistic effects on two bacteria causing food poisoning

Abstract

Lactic acid bacteria (LAB) is one of the main classes of acid-producing organisms in the food industry, and they play a vital part in many food and feed fermentations. We isolated and performed molecular identification of LAB from raw camel's milk and assessed their protective effects against pathogenicity induced by Staphylococcus aureus and Escherichia coli. Fourteen samples of camel's milk were obtained from several districts under aseptic conditions. Bacteria isolation was performed by plating the samples on selective media. Isolates were identified by amplification of the 16S ribosomal RNA by PCR and sequencing. A total of 32 isolates were randomly picked, eight of which were analysed in this study. On the basis of phenotypic and genotypic methods, isolated LAB was included Leuconostoc mesenteroides, Lactobacillus plantarum, Weissella paramesenteroides and Weissella confuse. Antagonistic activity of isolated LAB against two pathogenic bacteria showed that they had more inhibitory activity against S. aureus subsp. aureus PTCC 1431 than E. coli ATCC 25922. This study discovered that raw camel's milk obtained from three districts of Kerman province contain LAB bacteria that have antagonistic properties on S. aureus. Keywords: Camel, lactic acid bacteria, milk, probiotic