Effect of Hydrostatic Pressure Pulsing on the Inactivation ofSalmonellaEnteritidis in Liquid Whole Egg

Abstract

Eggs and egg-containing foods contaminated with bacterial human pathogens have been implicated in numerous foodborne outbreaks leading to costly recalls. Research was undertaken to investigate the use of high pressure-pulse treatment to inactivate Salmonella Enteritidis inoculated in liquid egg. Liquid egg was inoculated with Salmonella Enteritidis (8.0 log colony-forming units [CFU]/mL) and exposed to hydrostatic pressures (300-400 MPa) and pressure (350 MPa) pulsing at 25 degrees C, 40 degrees C, and 50 degrees C for up to 40 minutes to determine the maximum allowable pressure that can inactivate the Salmonella with minimal injury. Pressure treatments (350 and 400 MPa) at 25 degrees C for up to 40 minutes reduced the population of Salmonella Enteritidis by approximately 4.8 and 6.0 log(10) CFU/mL, respectively. High pressure (350 MPa) treatment at 50 degrees C and 2-minute pulses at four cycles for a total of 11.4 minutes, including the come-up and come-down times, led to a significant (p < 0.05) inactivation of Salmonella Enteritidis in liquid egg without causing coagulation. However coagulation occurred in the liquid egg at 400 MPa pressure treatment for 10 minutes at 50 degrees C. No Salmonella population was recovered in this liquid egg stored at 4 degrees C, 25 degrees C, and 37 degrees C for 24 hours suggesting that 350 MPa hydrostatic pressure and pulsing treatment is a better alternative for inactivation of Salmonella in liquid egg than continuous pressure treatment.