Survival and thermal resistance among four Salmonella serovars inoculated onto flaxseeds.

Thermal resistance among Salmonella serovars has been shown to vary, however, such data are minimal for Salmonella inoculated onto low moisture foods. We evaluated survival and subsequent thermal resistance for 32 strains of Salmonella from four serovars (Agona, Enteritidis, Montevideo, and Tennessee) on flaxseed over 24 weeks. After inoculation, flaxseeds were adjusted to a = 0.5 and stored at 22 °C. After 24 weeks at 22 °C, strains of serovar Agona had a significantly slower rate of reduction compared to those of Enteritidis and Montevideo (adj. p < 0.05). Inoculated flaxseeds were processed at 71 °C with vacuum steam pasteurization at 4 time points during storage. Average initial D values ranging from 1.0 to 1.5 min were similar across serovars. Over 24 weeks, D varied in a serovar-dependent manner. D at 8, 16, and 24 weeks did not change significantly for Enteritidis and Montevideo but did for Tennessee and Agona. While significant, the differences in D over time were less than 1 min, indicating that storage time prior to heat treatment would have a minimal effect on the processing time required to inactivate Salmonella on flaxseed.