UV-C treatments against Salmonella Typhimurium ATCC 14028 in Inoculated Peanuts and Almonds

Ultraviolet light C-region (UV-C) has been used for the disinfection of surfaces, water, and foods. Recently, Salmonellosis cases have been associated with the consumption of low moisture products, such as wheat flour and nuts. In this study, peanuts and almonds inoculated with around 10⁷ CFU/g of Salmonella enterica serovar Typhimurium ATCC 14028 were subjected to 2.5–30 min UV-C treatments (254 nm, 10 mW/cm², 10 cm between food and lamp). No reduction in the bacterium population was observed after 2.5 and 5 min for both nuts. Reductions of 0.68 and 2.39 log-cycles were observed after 30 min of treatment of peanuts and almonds, respectively. Weibull distribution described the inactivation of S. Typhimurium. After 30 min UV-C treatment, the temperature of peanuts and almonds increased 7.3 and 8.0°C, respectively, confirming that UV-C treatment is a non-thermal process. Water activity, color, and peroxides values were not affected by UV-C treatments (p > 0.05). UV-C light under the studied conditions was more effective for the treatment of almonds than peanuts. However, for both nuts, additional treatment conditions should be assessed to reach higher Salmonella inactivation values.