The potency of bacteriophages isolated from chicken intestine and beef tribe to control biofilm-forming bacteria, Bacillus subtilis

Biofilm becomes one of the crucial food safety problems in the food industry as the formation of biofilm can be a source of contamination. To deal with the problem, an industry generally employs physical and chemical methods including sanitizers, disinfectants, and antimicrobials to remove biofilm. However, the use of these methods may bring about new problems, which are bacterial resistance in the biofilm and the risk for product contamination. New strategies to deal with bacterial biofilms are needed. Bacteriophages (phages), as a green alternative to chemical, have re-emerged as a promising approach to treat bacterial biofilm. In the present study, the potential of lytic phages which have antibiofilm activity on biofilm-forming bacteria (Bacillus subtilis), were isolated from chicken intestines and beef tripe obtained from Indonesian traditional markets using host cells obtained isolated from these samples. Phages isolation was conducted by using double layer agar technique. A lytic test of phages was administered on biofilm-forming bacteria. The difference of turbidity level between control (which were not infected by phages) and the test tubes containing host bacteria infected by phages was investigated. The infection time for the production of phages was determined based on the level of clarity of the media in the test tube with a longer lysate addition time. Three phages were isolated namely: phi BS6, phi BS8, and phi UA7. It showed the ability to inhibit B. subtilis as biofilm-forming spoilage bacteria. The best inhibition results were obtained from phi BS6. Infection with phi BS6 in B. subtilis lead to 0.5 log cycle decreased in bacterial cells. This study showed that isolated phages might be used as a potential approach for handling the problem of biofilm formation by B. subtilis.