Effects of Fumigation on the Reduction of in Soil.

Due to the phaseout of methyl bromide (MeBr), there is a need for broad-spectrum soil fumigation alternatives for pest management. Little is known about the impact of fumigation alternatives on foodborne pathogens, such as , in agricultural soils. This study investigated the effect of MeBr alternative fumigants on reduction in soil. Sandy loam soil was collected from a conventional farmed vegetable field and inoculated with either Newport J1892 or Typhimurium ATCC 14028 (5.9 ± 0.3 log colony-forming unit [CFU]/g). Each of the four fumigants labeled for pest management (1,3-dichloropropene, chloropicrin, dimethyl disulfide, and metam sodium) was applied at labeled maximum application field levels to soil in pots and stored for a 2-week period. Sterile water was used as a control. Following the 2-week period, concentrations in soil samples were enumerated at 1, 7, 14, and 21 days postfumigation. The mean concentration of Newport was significantly higher than that of Typhimurium 1 day after fumigation ( = 0.015). Fumigation using 1,3-dichloropropene or dimethyl disulfide significantly reduced Newport and Typhimurium concentrations, compared with the sterile water control. The rate of reduction in soil treated with dimethyl disulfide was higher (0.17 ± 0.02 log CFU/g/day), compared with soil treated with the other fumigants (0.10-0.12 log CFU/g/day). Due to the reduction of , alternative fumigation treatments may mitigate potential contamination in soil within farm environments.