ANTIBIOTIC RESISTANCE AND ANTIBACTERIAL ACTIVITY OF DADIH ORIGINATED LACTOBACILLUS CASEI SUBSR CASEI R-68 AGAINST FOOD BORNE PATHOGENS

摘要

The expectations of probiotic bacteria have become the most demanding for any bacterial group. Probiotics have become a very important element to everyday health food products. The purposes of the study were to compare the antibacterial activity of Lactobacillus casei subsp. casei R-68 (LCR68) and Lactobacillus casei Strain Shirota (LCS) against food borne pathogens (Staphylococcus aureus FNCC-15, Listeria monocytogenes FNCC-0156, Escherichia coli FNCC-19 and Salmonella typhi) and evaluate the antibacterial compound responsible for inhibiting the food borne pathogens and to assay the resistance of both L. casei strains to various types of antibiotic. Assay for antibacterial activity was tested using the well diffusion method and test for resistanceto antibiotic was performed by employing disc diffusion method. The data obtained were tabulated and analyzed descriptively. The results showed that LCR68 and LCS inhibited the growth of Staphylococcus aureus FNCC-15, Listeria monocytogenes FNCC-0156 andEscherichia coli FNCC-19 but did not inhibit the growth of Salmonella typhi. In general, antibacterial activity of LCR68 was slightly lower than that of LCS. Both L. casei strains strongly inhibited the growth of Escherichia coli FNCC-19 than Listeria monocytogenes FNCC-0156 and Staphylococcus aureus FNCC-15, respectively. Antibacterial activity of LCR68 and LCS was resistant to heat treatment (60-95QC), amylase and various proteolitic enzymes, but was very sensitive to pH treatments (pH 4-9). Both LCR68 and LCS were also resistant to various types of antibiotic. It is concluded that antibacterial compound of LCR68 and LCS was organic acid mainly lactic and acetic acids.