Inhibition of Listeria monocytogenes in turkey and pork-beef bologna by combinations of sorbate, benzoate, and propionate

The control of Listeria monocytogenes was evaluated with ready-to-eat uncured turkey and cured pork-beef bologna with combinations of benzoate, propionate, and sorbate. Three treatments of each product type were formulated to include control with no antimycotic agents; a combination of 0.05% sodium benzoate and 0.05% sodium propionate; and a combination of 0.05% sodium benzoate and 0.05% potassium sorbate. Ingredients were mixed, stuffed into fibrous, moisture-impermeable casings, cooked to an internal temperature of 73.9 degrees C, chilled, and sliced. The final product was surface inoculated with L. monocytogenes (4 log CFU per package), vacuum packaged, and stored at 4 degrees C for 13 weeks. The antimycotic addition to the second and third uncured turkey treatments initially slowed the pathogen growth rate compared with the control, but populations of L. monocytogenes increased 5 log or more by 6 weeks. In contrast, the addition of antimycotic combinations in the cured bologna prevented growth of L monocytogenes during the 13-week storage period at 4 degrees C, compared with a more than 3.5-log increase in listerial populations in the control bologna, to which no antimicrobial agents had been added. These data suggest that low concentrations of antimycotic agents can prevent L monocytogenes growth in certain ready-to-eat meats. Additional research is needed to define the levels needed to prevent growth of L. monocytogenes in high-moisture cured and uncured ready-to-eat meat and poultry and for gaining governmental approval for their use in such formulations.