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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #368398

Research Project: Ecology and Detection of Human Pathogens in the Produce Production Continuum

Location: Produce Safety and Microbiology Research

Title: Viability of listeria monocytogenes and salmonella typhimurium after isochoric freezing

item Bridges, David
item Bilbao-Sainz, Cristina
item POWELL-PALM, MATTHEW - University Of California
item Williams, Tina
item Wood, Delilah - De
item Sinrod, Amanda
item UKPAI, GIDEON - University Of California
item McHugh, Tara
item RUBINSKY, BORIS - University Of California
item Wu, Vivian

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2020
Publication Date: 8/10/2020
Citation: Bridges, D.F., Bilbao-Sainz, C., Powell-Palm, M.J., Williams, T.G., Wood, D.F., Sinrod, A., Ukpai, G., McHugh, T.H., Rubinsky, B., Wu, V.C.H. 2020. Viability of listeria monocytogenes and salmonella typhimurium after isochoric freezing. Journal of Food Safety. 40(5). Article e12840.

Interpretive Summary: During conventional freezing processes, ice formation and osmotic stress can cause substantial cellular and tissue damage which can significantly deteriorate the quality of food products. This process can simultaneously have an antimicrobial effect as well. Isochoric freezing is an emergent low-temperature food storage method that enables preservation of biological tissues at subfreezing temperatures at an elevated level of pressure without the formation of ice. However, this technology could potential protect pathogenic microorganisms as well. Therefore, the object of this study was to evaluate the viability of Listeria monocytogenes and Salmonella enterica after storage in isochoric conditions. Our results show a noticeable increase in bacterial log reductions that would not be expected from exposure to low temperatures or elevated pressures alone. These data indicate that the two conditions (low temperature and pressure) could be working synergistically to destroy bacterial populations at rates far greater than those achieved by the application of one condition or the other independently.

Technical Abstract: Effective inactivation of pathogenic bacteria is essential to food safety, and presents an ongoing public health issue in the 21st century. In this work, we use an isochoric freezing system to demonstrate that the synergistic combination of moderate cold (-15ºC) and moderate high pressure (135MPa) enables extreme degrees of bacterial inactivation typically attainable only at 500 MPa or greater at room temperature, and unachievable under low-temperature atmospheric pressure conditions alone.