| Abstract [eng] |
Thermophilic bacteria pose a major threat to food processing plants. These bacteria are very difficult to eliminate due to their high temperature tolerance and spore formation, so attempts are being made to find faster methods of inhibiting their growth. One such method is antimicrobial photodynamic therapy, which has long been used in medicine and in microbial control departments. This therapy is defined as an oxygen-dependent photochemical reaction that takes place through the activation of photosensitisers by light, resulting in the production of cytotoxic reactive oxygen species. This therapy is gaining a lot of attention due to its high efficacy, specificity and minimal side effects. Since very little information is available on the application of antimicrobial photodynamic therapy to thermophilic bacteria, this work was undertaken to analyse its effect on thermophilic Parageobacillus toebii cells. The bacteria studied were inactivated by LEDs emitting 440 nm and 402 nm light. The natural photosensitisers chlorophyllin, riboflavin and curcumin were tested. Experiments were also carried out in combination with bacteriocin nisin. The effectiveness of photodynamic therapy was evaluated by the number of colonies grown at different doses of irradiation. According to the results obtained, chlorophyllin is the most effective FS for inhibiting the growth of P. toebii. The nisin-chlorophyllin combination also had the greatest effect on the cells and was observed to be the most effective in all aFDT tests. |
