Listeria monocytogenes has been implicated
in outbreaks of illness involving ready-to-eat (RTE) meat products, prompting researchers to look into intervention
technologies to reduce or eliminate this
risk. In our study roast beef was inoculated
with a 5-strain cocktail of Listeria monocytogenes, vacuum-packaged, and then
pasteurized at 205°F for 0, 2, 3 or 4 min in
a Stork RMS-Protecon Post-Process Pasteurization System. More bacteria were
killed as pasteurization time increased. Initial inoculum level was 5.8 log10 CFU/cm2
of product surface area. Pasteurization for
2 min resulted in 2.5 to 2.7 log10 CFU/cm2
reductions. Similar reductions were seen at
3 min. At 4 min pasteurization, L. monocytogenes decreased in roast beef by approximately 4.5 log10 CFU/cm2; over
99.99% had been killed. The Stork steam
based system is effective for reducing the
risks of L. monocytogenes in RTE roast
beef while providing acceptable quality
characteristics.
