Evaluating the effect of X ray irradiation in the control of food bacterial pathogens

Abstract

Food-born pathogens need to be controlled in food industry. The efficiency of X ray irradiation to eliminate pathogens has been shown but the efficient dose of irradiation has not been standardized. The optimum dose, which controls pathogenic bacteria and does not deteriorate food quality, needs studies on many different foods. The efficiency of different energy levels of X-ray irradiation and the treatment cycles needed to control food bacteria were tested. X ray doses of 0.1, 0.5, 1.0, 1.5 and 2.0 kGy/sec for 10 min (3 cycles) were used to solid and liquid foods, which were experimentally inoculated with bacterial pathogens Campylobacter jenjuni, Brucella abortus, Escherichia coli, Bacillus cerus, and Clostridium perfringes. The inoculation resulted high bacterial contamination, the colony forming units (CFU) were too high to be counted. After one cycle of irradiation with the highest dose, more than 100 CFU was counted. The efficient treatment was three cycles of 2.0 kGy irradiation, where no bacterial growth was observed. The dose of 1.5 gGy was almost as efficient. The lowest dose, 0.1 kGy, gave ca 10 CFU after three cycles. The analysis of sugar, fat, protein, and vitamins showed no change due to X ray irradiation indicating no deterioration of food quality. X ray irradiation technique is an efficient technique to control food-born pathogens and prevent food-born illnesses.