1. Introduction
Poo-Khem is a traditional salted crab widely consumed in Thailand. It is made from crab, salt and water
and fermented with the natural microflora [1]. The fermentation process of Poo-Khem was based on the
natural microflora. The microbial quality of this product were depended on the species and loads of
pathogenic bacteria as well as the number of lactic acid bacteria. In the previous study, they found that Poo-
Khem was contaminated with pathogenic bacteria such as Bacillus cereus, Escherichia coli, Salmonella
Typhimurium and Staphylococcus aureus while LAB were found in a small number [2]. The present of
pathogenic bacteria in Poo-Khem may cause direct negative effects on human health.
Lactic acid bacteria are widely employed in industrial fermentation processes and as starter cultures in
the fermented foods. Especially, LAB with probiotic properties are used as adjuncts in food to provide a
wide variety of health benefits. High tolerance at low pH and bile salts considered as important selection
criteria for probiotic. Another criterion of the probiotic culture includes the ability to adhere the intestinal
epithelium cell and the ability to inhibit the pathogenic bacteria [3]. Probiotic LAB with antimicrobial
activity has attracted much attention as they can be used to enhance the hygienic quality of the product by
inhibit the growth of pathogenic bacteria. In this study, lactic acid bacteria which isolated from Poo-Khem
were screened for their antimicrobial activity against 6 food-borne pathogenic bacteria and some probiotic
properties such as pH and bile tolerances, ability to growth under anaerobic condition and in vitro adhesion.
Then selected probiotic LAB were subjected to identify by 16S rDNA sequencing analysis.