Destruction of Listeria monocytogenes and Shelf-life Extension of Sliced Roast Beef and Turkey Breast by High Pressure Processing

Introduction: Ready-to-Eat (RTE) meat and poultry processors follow enhanced sanitation practices, use antimicrobial agent and/or process or apply post-lethality process to minimize the risk L. monocytogenes.

Purpose: Evaluate destruction of L. monocytogenes by HHP and extension of shelf life of sliced turkey breast and roast beef during refrigerated storage.

Methods: Turkey breast and roast beef (sliced) were obtained from a commercial processor and stored under refrigeration. A slice of either product was inoculated with a 5-strain cocktail of L. monocytogenes to attain ca. 3.0 log CFU/cm² (low) or 5.0 log CFU/cm² (high) on the product. The inoculated slice was placed between non-inoculated product and vacuum packaged. Non-inoculated products were processed and used for evaluation of microbial shelf life. Products were processed at 87,000 psi for 2 (HPP-2 min) or 3 (HPP-3 min) min and stored at 4°C. L. monocytogenes survival and microbial shelf life (total plate counts, TPC) was determined after processing (0 day), 30, 60, 90 and 120 days of storage. 

Results: HPP for 2 or 3 min resulted in L. monocytogenes reductions of 5.29 and 5.52 log CFU/cm² on roast beef and 2.85 and 4.48 log CFU/cm² on turkey breast, respectively. HPP of roast beef and turkey breast resulted in elimination of L. monocytogenes on product inoculated at low level (ca. 2.93 log CFU/cm²) on both the products. The TPCs of roast beef were 5.24, 4.13 and 4.70 log CFU/cm² for control, HPP-2 min and HPP-3 min, respectively, after 90 days of storage. TPCs of turkey breast were 6.23, 2.07 and 2.26 log CFU/cm²for control, HPP-2 min and HPP-3 min, respectively, after 90 days of storage.

Significance: HPP is an effective post-lethality treatment to eliminate L. monocytogenes contamination on sliced roast beef and turkey breast and improve microbial shelf life of the products.