The effects of UV , gamma‐ and X‐ray irradiation on the growth, antibacterial activity and radio‐protective of Lactobacillus rhamnosus

Abstract Ionizing radiation is widely applied in food production as preservation technology and for correction of the gut microbiome of cancer patients, rescuers, astronauts etc. Lactic acid bacteria (LAB) can be used for the same reason. The main goal of this study was to investigate the effect of irradiation on some activities of Lactobacillus rhamnosus MDC 9661 and its effect on the survival of irradiated rats. The results indicate that both ultraviolet (during 45 min) and X-ray irradiations (with 2 Sv) decreased the CFU and the antibacterial activity of the strain. Higher than 700 Sv dose of X-ray irradiation resulted in the total inhibition of antibacterial activity with the total reduction of colony forming units less than 10 cells ml−1, while irradiated with 1000 Sv dose L. rhamnosus MDC 9661 did not lose its proteolytic activity. It was also shown that L. rhamnosus MDC 9661 was not immunogenic in the organism of the rats and cannot lead to the development of autoimmune responses. L. rhamnosus MDC 9661 demonstrated the necessary properties for probiotics and can be effectively used for the correction of the gut microbiome of all target groups. The co-aggregation of the cells is one of the mechanisms for resistance of LAB to irradiation.