Effects of Thermally-Assisted and High-Pressure Processing on Background Microbiota and the <i>Listeria monocytogenes</i> Load of a Minimally Processed Commodity

Abstract

The current study investigated the impact of treatments with elevated hydrostatic pressure (500 MPa) for inactivation of Listeria monocytogenes on smoked rainbow trout (Oncorhynchus mykiss) at high and low inoculation levels. The temperature values of the trials were set at 4.4 and 60.0 °C, adjusted with a circulating water bath connected to a stainless steel jacket surrounding the pressure processing chamber. Before pressure processing, the counts (selective counts of PALCAM, mean ± SD) of L. monocytogenes were 6.45 ± 0.1 log CFU/g and were reduced (p p max1 were 8.68 and 0.50, and 5.81 and 2.41 for high-inoculation and low-inoculation samples, respectively. Application of hydrostatic pressure at 500 MPa at cold and elevated temperatures was efficacious for up to 5.03 log CFU/g reduction of L. monocytogenes, illustrating the potential for further adaptation of this technology.

Keywords

• high-pressure processing
• <i>Listeria monocytogenes</i>
• background microbiota