Purpose: The objective of this study was to determine the effect of using buffered vinegar powder at low levels (0.25%) as a secondary inhibitor in high-pressure processed RTE products to prevent outgrowth of LM introduced during slicing after HPP packages are opened.
Methods: Turkey, beef and ham were formulated with vinegar at 0.25% and subjected to 87,000 psi for 3 min; product packages were opened, sliced and surface inoculated with a five-strain cocktail of LM (3 log CFU/g), heat sealed and stored at 39±1ºF.Pathogen outgrowth was evaluated (n=3) for 14 days using modified oxford medium (MOX). Control samples received HPP and no vinegar treatment.
Results: Results indicate that pathogen outgrowth (LM, ≥2 log CFU/g) occurs in absence of a secondary inhibitor after high-pressure processed product packages are opened and sliced. In the presence of vinegar, in beef and ham, only 1.81 and 1.03 log CFU/g increase was seen in 14 days. In turkey however, a 2 log CFU/g increase was seen after day 11 and an increase of 2.41 log CFU/g was observed at day 14. Turkey and beef control samples (without vinegar) showed ≥2 log CFU/g increase in LM in 7 days while ham control showed the same increase at day 11.
Significance: Introducing vinegar powder as a secondary inhibitor in RTE meat and poultry formulations can prevent outgrowth of LM in high-pressure processed products once the original package is opened and product is sliced.