Inactivation of foodborne pathogens on leek and alfalfa seeds with supercritical carbon dioxide

This study aimed to evaluate the effect of supercritical CO2 process for the inactivation of artificially contaminated seeds of leek and alfalfa. The seeds were inoculated with E. coli O157:H7, Listeria monocytogenes, and Salmonella Thompson and S. Typhimurium and treated at 80 and 120 bar and at 35 and 45 °C for 20 min. The process did not influence the germination rate of the seeds. The inactivation was dependent from the type of seed and pressure and temperature. At 120 bar and 45 °C E. coli O157:H7, L. monocytogenes, and Salmonella spp. were reduced by 2.92 ± 0.27, 1.14 ± 0.63, and 1.74 ± 0.55 log CFU/g, respectively, on alfalfa and by 4.96 ± 0.37, 2.93 ± 0.27, and 3.18 ± 0.27, respectively on leek. Overall, these results indicated that supercritical CO2 can be used to improve the microbial safety of sprouts, especially for leek.