Effects of high-pressure processing on the safety, quality, and shelf life of ready-to-eat meats

Abstract

Ready-to-eat (RTE) meats (low-fat pastrami, Strassburg beef, export sausage, and Cajun beef) were pressure treated at 600 MPa, 20°C, for 180 s to evaluate the feasibility of using high-pressure processing (HPP) for the safe shelf-life extension of these products. After processing, samples were stored at 4°C for 98 days during which time microbiological enumeration and enrichments were performed. Additionally, sensory analyses were undertaken to determine consumer acceptability and purchase intent over the duration of storage. Counts of aerobic and anaerobic mesophiles, lactic acid bacteria, Listeria spp., staphylococci, Brochothrix thermosphacta, coliforms, and yeasts and molds revealed that there were undetectable or low levels for all types of microorganisms throughout storage. Comparison of consumer hedonic ratings for unprocessed and processed meats revealed no difference in consumer acceptability, and no deterioration in the sensory quality was evident for any of the products tested during the study. Additionally, inoculated pack studies were conducted to determine if HPP could be used as a postlethality treatment to reduce or eliminate Listeria monocytogenes and thus assess the potential use of HPP in a hazard analysis critical control point plan for production of RTE meats. Inoculated samples (initial level of 104 CFU/g) were pressure treated (600 MPa, 20°C, for 180 s) and stored at 4°C, and survival of L. monocytogenes was monitored for 91 days. L. monocytogenes was not detected by plating methods until day 91, but selective enrichments showed sporadic recovery in three of the four products examined. The results show that HPP at 600 MPa, 20°C, for 180 s can extend the refrigerated shelf life of RTE meats and reduce L. monocytogenes numbers by more than 4 log CFU/g in inoculated product.