Effects of high hydrostatic pressure and varying concentrations of sodium nitrite from traditional and vegetable-based sources on the growth of Listeria monocytogenes on ready-to-eat (RTE) sliced ham

The objective of this study was to determine the effect the source of added nitrite and high hydrostatic pressure (HHP) had on the growth of Listeria monocytogenes on ready-to-eat (RTE) sliced ham. Use of 600 MPa HHP for 3 min resulted in an immediate 3.9–4.3 log CFU/g reduction in L. monocytogenes numbers, while use of 400 MPa HHP (3 min) provided less than 1 log CFU/g reduction. With the 600 MPa HHP treatment, sliced ham with a conventional concentration of sodium nitrite (200 ppm) was not different in L. monocytogenes growth from use with 50 or 100 ppm of sodium nitrite in pre-converted celery powder. Instrumental color values as well as residual nitrite and residual nitrate concentrations for cured (sodium nitrite and nitrite from celery powder) and uncured ham formulations are discussed.