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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Food Safety and Intervention Technologies Research » Research » Publications at this Location » Publication #202906
Title: Effect of Hydrostatic Pressure Pulsing on the Inactivation of Salmonella Enteritidis in Liquid Whole Egg

Author
item BARI, M - NAT'L FOOD RES INSTITUTE
item Ukuku, Dike
item MORI, M - IFUJI SANGYO CO,LTD JAPAN
item KAWAMOTO, S - NAT'L FOOD RES INSTITUTE
item YAMAMOTO, K - NAT'L FOOD RES INSTITUTE

Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2007
Publication Date: 4/1/2008
Citation: Bari, M.L., Ukuku, D.O., Mori, M., Kawamoto, S., Yamamoto, K. 2008. Effect of Hydrostatic Pressure Pulsing on the Inactivation of Salmonella Enteritidis in Liquid Whole Egg. Foodborne Pathogens and Disease. 5(2):175-182.

Interpretive Summary: In recent years, Salmonella in eggs has emerged as a major concern for public health agencies and the risk of illness is greater when the egg is used as an ingredient in a food that is consumed by many people rather than when it is a single egg. Thermal pasteurization of liquid egg changes the functional properties of the egg leading to protein denaturation and coagulation. Also, because of the high-energy demands involved with thermal pasteurization, we proposed that repeating minimal hydrostatic pressure would inactivate Salmonella in liquid egg without causing coagulation in the eggs. Liquid whole egg inoculated with Salmonella enteritidis at 8.0 log CFU/ml were treated with continuous or repeating hydrostatic-pressures (300 MPa to 400 MPa) at 25C, 40C and 50C for up to 40 min. Treatments of 350MPa and 400 MPa pressure at 25C for 40 min reduced the population of S. enteritidis by approximately 4.8 and 6.0 log10 CFU/ml in liquid whole egg, respectively. Pressure treatments at 350 MPa and 400 MPa at 50C for 10 min resulted in more than 6 log inactivation of Salmonella however, protein coagulation in liquid egg occurred at 400 MPa treatment. Repeating pressure treatment (350 MPa at 50C) every two (2 min) for a total of 8 min at 4 cycles caused significant (P<0.05) bacteria inactivation (greater than 5 log reduction) and the population of Salmonella recovered after HPP treatment and storage at 4, 25, and 37C for 24 h was less than 2 CFU/ml. The results of this study suggest that repeating 350 MPa pressure treatments at least 4 times for a total of 8 min would achieve total inactivation of Salmonella in liquid whole egg than continuous pressure treatment.

Technical Abstract: Salmonella in Eggs and egg-containing foods have caused numerous food-borne outbreaks and recalls. Liquid whole egg inoculated with Salmonella enteritidis at 108 CFU/ml were treated with continuous or repeating hydrostatic -pressures (300 MPa to 400 MPa) at 25C, 40C and 50C for up to 40 min. Treatments of 350MPa and 400 MPa pressure at 25C for 40 min reduced the population of S. enteritidis by approximately 4.8 and 6.0 log10 CFU/ml in liquid whole egg, respectively. Liquid whole egg treated at 350 MPa pressure for 10 min at 50C showed the highest inactivation of Salmonella. However, pressure treatment at 400 MPa for 10 min at the same temperature (50C) caused coagulation of protein in liquid egg. When treatment pressure (350 MPa at 50C) was repeated every two (2 min) for a total of 8 min at 4 cycles, a significant (P<0.05) bacteria inactivation occurred. No Salmonella was recovered in liquid egg after pressurization (2 min x 4 cycles) and storage at 4, 25, and 37C for 24 h. The results of this study suggest that repeating 350 MPa hydrostatic-pressure treatments at least 4 times for a total of 8 min would lead to higher inactivation of Salmonella in liquid whole egg than continuous pressure treatment.