CONTROL OF LISTERIA MONOCYTOGENES IN HAM DELI LOAVES USING ORGANIC ACIDS

Combinations of organic acids, sodium lactate (SL; Fisher Scientific Co. LLC., Pittsburgh, PA), potassium lactate (PL; City Chemical LLC., West Haven, CT) and sodium diacetate (SD; Spectrum Chemical MFG. Corp., Gardena, CA), were applied in the raw product and as a post-cook dip to determine their inhibitory effect on Listeria monocytogenes in ham deli loaves. Loaves were formulated with an organic acid as an ingredient, cooked, cooled, inoculated with streptomycin-resistant L. monocytogenes and then dipped in an organic acid treatment. Treatments consisted of PL in the raw product and PL in the dip, PL with SL/PL/SD dip, SL/SD with PL dip, and SL/SD with SL/PL/SD dip. Loaves were examined on a weekly basis for 56 days. Treatments containing PL with SL/PL/SD, SL/SD with PL, and SL/SD with SL/PL/SD had similar inhibition effects on L. monocytogenes from day 0 to day 42 (P < 0.05). On day 56, the PL with SL/PL/SD and the SL/SD with SL/PL/SD treatments were similar (P < 0.05). The PL with SL/PL/SD, SL/SD with PL, and SL/SD with SL/PL/SD treatments increased the lag phase of L. monocytogenes compared with distilled water control (P < 0.05). PRACTICAL APPLICATIONS Including a food grade organic acid-based product in the formulation and as a post-cook dip treatment can result in the slower growth of Listeria monocytogenes in deli ham loaves. This approach could provide meat processors with a useful method for controlling this deadly pathogen in ready-to-eat meat products.