Hot Water Shrinkage as a Post-Lethal Intervention against Listeria Monocytogenes: Preliminary Assessment in a Turkey-Based Virginia Ham Model

This preliminary laboratory trial evaluated the potential of hot water shrinkage to reduce post‐lethal surface contamination by Listeria monocytogenes (Lm) in a turkey‐based Virginia ham model. We inoculated triplicate of ham slices (10 cm2, 2‐cm thick) with 105 cfu/cm2 of Lm (ATCC 19114). Subsequently, they were vacuum‐packaged and placed in a thermostated water bath at 75, 80, 85 and 90C for 0, 20, 25 and 30 s. Treatment at 75–85C for up to 30 s did not affect Lm survival, while nearly 4‐log reduction was observed at 90C for 30 s. The strong correlation (r = 0.9685–0.9891) between results and estimated lethalities (from previous inactivation data) highlights the potential of the 90C/30 s regimen as an effective post‐lethal intervention. However, these results should be used with caution as they may vary under different industry conditions. Further research is needed to develop an appropriate pathogen reduction model for this process. Practical Applications Hot water shrinkage has a promising application in controlling post‐lethal surface contamination by Listeria monocytogenes in some deli meats. This intervention is likely to be cheaper than regular post‐package pasteurization. It is also feasible, from a productivity standpoint, in many medium‐sized companies. The latter may work only for products with a smooth surface and a composition similar to that of the turkey‐based Virginia ham tested in this study.