Effects of High Hydrostatic Pressure on Heat‐Resistant and Heat‐Sensitive Strains of Salmonella

Abstract

ABSTRACT Salmonella senftenberg 775W, a heat‐resistant strain (D 57.5°C = 15.0 min) and Salmonella typhimurium ATCC 7136, a heat‐sensitive strain (D 57.5°C =3.0 min), were subjected to hydrostatic pressures of 2,380 to 3,400 atmospheres (atm) at 23°C in phosphate buffer (63 mM, pH 7.0) and chicken medium (strained baby food). Survivor curves showed that cell death occurred in this pressure range and increased as pressure increased. Death was greater in buffer than in the chicken medium. S. senftenberg 775W was more sensitive to pressure than S. typhimurium 7136. Injury occurred over the range of pressures for both species. Recovery at 37°C was possible following pressurization for salmonellae in chicken but not in buffer.