High hydrostatic pressure inactivation kinetics of Salmonella typhimurium

Abstract

The inactivation kinetics of high hydrostatic pressure for Salmonella typhimurium (KUEN 137) inoculated in tryptone soy broth (TSB) and foods (raw milk and orange juice) were studied from 250 to 400 MPa, 15–45 °C and pH adjusted from 5.0 to 7.0. The rate of inactivation of S. typhimurium during the initial 10 min was far greater than during the remaining treatment time. The inactivation of S. typhimurium showed two-phase inactivation (fast to slow). Decimal reduction times (D value) for S. typhimurium in the second phase were 4.61, 2.59, 2.09, and 1.80 min at 250, 300, 350, and 450 MPa, respectively, in TSB after 10 min (second phase). D values were 1.75 and 1.50 min for S. typhimurium in milk and orange juice, respectively, at 300 MPa (second phase) and the k values were 1.32 and 1.54 min⁻¹, respectively (second phase). The rate of inactivation increased in increasing temperature and there were significant (P<0.05) reductions in the S. typhimurium at treated temperatures, pressures, and pH. The use of inactivation could be beneficial to the food industry for optimizing process conditions.

Keywords:

• high hydrostatic pressure
• inactivation
• kinetic
• S. typhimurium

Acknowledgements

This paper was supported by the Gaziantep University Research Fund.