Effects of Sodium Lactate on the Survival of Listeria Monocytogenes, Escherichia coli O157:H7, and Salmonella spp. in Cooked Ham at Refrigerated and Abuse Temperatures

The objective of this study was to determine the effect of sodium lactate on the survival of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp. in cooked ham during storage at refrigerated and abuse temperatures. Cooked ham was added with 0% 3% lactate, inoculated with a multiple-strain mixture of L. monocytogenes, E. coli O157:H7, or Salmonella spp. and stored at 4 ̊C 15 ̊C for up to 35 day. The growth of the three pathogens was inhibited in ham containing 3% lactate, and no growth of E. coli O157:H7 and Salmonella spp. occurred at the lowest storage temperatures of 6 and 8 ̊C, respectively. In ham containing no lactate, the average growth rates were 0.256 0.380 log CFU/day for L. monocytogenes at 4 ̊C 8 ̊C, 0.242 0.315 log CFU/day for E. coli O157:H7 at 8 ̊C 15 ̊C, and 0.249 0.328 log CFU/day for Salmonella spp. at 10 ̊C 15 ̊C. The addition of 1% or 2% lactate significantly (P < 0.05) reduced the growth rates of the three pathogens, and the effect was more profound at lower temperatures. Salmonella spp. were more sensitive to the effect of lactate than L. monocytogenes and E. coli O157:H7. Polynomial models were developed to describe the growth rates of the three pathogens as affected by the lactate concentration and storage temperature. Results from this study demonstrate the effect of lactate on the growth of L. monocytogenes, E. coli O157:H7, and Salmonella spp. in cooked ham and indicate the effective lactate concentrations and storage temperatures that can be used to enhance the microbiological safety of ready-to-eat ham products.