Environmental factors affecting survival of Campylobacter jejuni in vacuum packaged processed turkey

The effect of nitrite upon growth and survival of Campylobacter jejuni, and the effect of vacuum packaged storage at 4°C upon survival of C. jejuni in processed turkey ham and turkey were evaluated. Minimum inhibitory concentrations (MIC) and minimum lethal concentrations (MLC) of sodium nitrite for C. jejuni were determined at pH 6.0 and 7.0 by a modified tube dilution method. The MIC and MLC at both pH levels ranged from 200-1100 ppm and were above the legal limit of sodium nitrite that could be added to meats. It was concluded that sodium nitrite alone at <156 ppm would not inhibit growth and survival ofC. jejuni in cured meats having a pH greater than 6.0. To determine the effect of vacuum packaged storage on survival of C. jejuni, turkey ham and turkey roll samples were sliced, inoculated with C. jejuni, vacuum packaged, and stored at 4°C for 0, 1, 3, 7, 10, and 14 d. An additional set of samples were prepared for turkey ham to extend storage to 28 d. Three different strains of C. jejuni were evaluated. An inoculated sample for each strain and a control sample with no inoculum were prepared for each sample and each storage period. After appropriate incubation, the inoculated samples were analyzed for surviving C. jejuni. Control samples were analyzed for aerobic plate count. Survival of C. jejuni during vacuum packaged storage at 4°C decreased significantly over time (P<0.05). A significant difference in viability existed between the three test strains used (P<0.05). Survival of C. jejuni was better in the turkey ham than the turkey roll. Aerobic plate count increased significantly during storage (P<0.05) providing atagonistic competition for C. jejuni survival. Though survival of C. jejuni decreased over time, viable cells were detected up to 28 d. Apparently, the effect of vacuum packaged storage at 4°C in turkey ham and turkey roll upon survival of Campylobacter jejuni was inhibitory, though not immediately lethal.