Effect of Hydrostatic Pressure Pulsing on the Inactivation of Salmonella Enteritidis 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°C, 40°C, and 50°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°C for up to 40 minutes reduced the population of Salmonella Enteritidis by approximately 4.8 and 6.0 log₁₀ CFU/mL, respectively. High pressure (350 MPa) treatment at 50°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°C. No Salmonella population was recovered in this liquid egg stored at 4°C, 25°C, and 37°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.