Ultralow temperature high pressure processing enhances inactivation of norovirus surrogates

Authors: DEWITT, CHRISTINA - Oregon State University; NELSON, KEVIN - Oregon State University; KIM, HYUNG JOO - Oregon State University; Kingsley, David

Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2023
Publication Date: 10/6/2024
Citation: Dewitt, C.A., Nelson, K.A., Kim, H., Kingsley, D.H. 2024. Ultralow temperature high pressure processing enhances inactivation of norovirus surrogates. International Journal of Food Microbiology. 408:110438. https://doi.org/10.1016/j.ijfoodmicro.2023.110438.
DOI: https://doi.org/10.1016/j.ijfoodmicro.2023.110438

Interpretive Summary: This publication demonstrates that virus inactivation by high pressure processing can be dramatically enhanced as a result of ultra-low temperature 35 degrees below Celsius as well as keeping the sample thawed prior to pressurization in ultracold conditions. This work should have applications for RTE frozen foods intended to be consumed raw. It both provides a potential way to treat frozen foods and potentially a unique process by which foods are both HPP-treated and frozen at the same time.

Technical Abstract: High pressure processing (HPP) is a powerful non-thermal method for inactivating pathogens and viruses within foods. Human norovirus and genetically–related caliciviruses are moderately sensitive to temperatures above 0 degrees C with greater than 400 MegaPascals (MPa) or higher required to inactivate multiple logs of virus. Sensitivity of murine norovirus (MNV) and Tulane virus (TV) to ice phase transitions was evaluated using ultra low temperature HPP. Targeted phase transitions were liquid to type III and ice I to III. Identical samples were either equilibrated to 1.5 degrees Celsius or 40 degrees below zero Celsius 24 h prior to pressurization. Samples were placed in a pre-chilled chamber with 40 degrees below Celsius chamber fluid placed into the chamber immediately prior to pressurization. Samples are pressurized for 5 minutes at 200, 250 and 300 MPa. For MNV, 5 min-200 MPa treatments of samples initially at 1.5 degrees Celsius had average log reductions of 4.4, while greater than 6.1 log reduction (non-detectable) at 250 and 300 MPA were observed. TV samples averaged 2.3, 5 and 4.3 log reduction at 200, 250, and 300 MPa respectively. For MNV, 5 minute treatments of samples initially at 40 degrees below Celsius prior to initial pressurization, averaged 2.3, 3.2 and 4.2 at 200 MPA, 250 MPa and 300 MPa, respectively while TV samples averaged 0.81, 2.3 and 1.7 log reductions at 200, 250, and 300 MPa, respectively. Results indicate that in addition to enhancing inactivation of norovirus surrogates compared to warmer temperatures, ultra-cold HPP performed on thawed samples especially enhances inactivation.