Effect of uranium on the radiosensitivity of Salmonella spp. in pork meat

The presence of natural radionuclides in the chain of pig meat production, especially in food and feed additives (premixes), as the most important mutagenic factor, could significantly affect the variability of Salmonella isolates in the pork chain. In the first stage of the study, outlined in this paper, the goal was to determine if radioactivity has any effect on survival/growth of Salmonella in pigs meat. We studied six strains of Salmonella that were exposed to four levels of radioactivity. The differences in Salmonella counts between pork meat homogenates with or without added radioactive uranium were following: the Salmonella counts (log(10) CFU/ml) in control meat homogenate (without added radioactivity) increased from the level of around 7.4 logs (at 30 min storage) to around 9.0 logs, due to growth of the pathogen. No significant differences in this general pattern were observed between the 6 Salmonella serovars tested in the control meat homogenates (without added radioactivity). On the other hand, Salmonella counts in meat homogenate with added radioactivity U-238 (1, 2, 5, 10 kBq) decreased (by around 1-1.5 logs) practically immediately after addition of the uranium, compared with control meat homogenates. Subsequently, Salmonella also grew during storage of meat homogenate with added radioactivity, but to a lesser extent than in control meat homogenates. Salmonella enteritidis (2) had the highest factor reduction in meat homogenates with radioactivity added 238U (1, 2 kBq). It had the highest reduction factor around 1.57 to 1.67 logs. In contrast, Salmonella tiphimurium (3) had the highest factor reduction in meat homogenates with radioactivity added 238U (5, 10 kBq), which ranged from 1.83 to 1.96 logs.