Overview

This application allows the user to determine the milk hold time and temperature necessary for log-reductions of 2 foodborne bacterial pathogens pertinent to cheeses (Listeria monocytogenes, Shiga-toxin producing Escherichia coli) made with unpasteurized bovine milk; this app has been updated July 2025 to include inactivation of H5N1 virus (“avian influenza”) that has been circulating in certain regions of the US since March 2024. Please read all disclaimers before use. Cheeses made using milk with higher fat or solids content (e.g. sheep’s milk) are outside the scope of this application. Use of time / temperature treatments does not negate requirements for manufacturing cheeses under Good Manufacturing Practices.

Use the drop-down menus to select your microbe of choice (Listeria monocytogenes, Shiga-toxin producing Escherichia coli, or H5N1) and your desired log-reduction of the chosen microbe (3-, 4-, 5-, or 6-log kill; H5N1 is set for 7-log reduction only). To make selections, hover over the “Microbe” or “Reduction” field, click, and highlight your selection. Repeat for the second field.

A temperature range of 140°F to 155°F in whole degree increments is included in the application for bacterial pathogens; H5N1 temperature range is between 130 and 145°F. To make selections for temperature, hover over the gray circle located by default at the far left of the slider. Click and hold the gray circle and slide it along the temperature axis, releasing when at your desired temperature. Alternatively, click a temperature along the axis to select, or choose °F  from temperature pull down menu. Outputs to the right of the application (“Hold Time”, in seconds, and log-reduction of unselected pathogen) will change in real-time according to the temperature selected.

E.g. Selecting Shiga-toxin producing Escherichia coli and 3-log kill requires a hold time of 64 seconds at 145°F; a 1.22-log reduction of Listeria monocytogenes and a 6.7 log reducing of H5N1is anticipated with this same treatment.

For additional information, please reference

Determination and Validation of D-Values for Listeria monocytogenes and Shiga Toxin-Producing Escherichia coli in Cheesemilk, Journal of Dairy Science, 2021, https://doi.org/10.3168/jds.2021-20350 by S. K. Engstrom, M. F. Mays, and K. A. Glass.

Thermal inactivation spectrum of influenza A H5N1 virus in raw milk. Nat Commun 16, 3299 (2025). Nooruzzaman, M., Covaleda, L.M., de Oliveira, P.S.B. et al. https://doi.org/10.1038/s41467-025-58219-1 by Nooruzzaman M, Covaleda LM, de Oliveira PS, Martin NH, Koebel KJ, Ivanek R, Alcaine SD, Diel DG.

Research for thermal inactivation of Listeria monocytogenes and Shiga-toxin producing E. coli was funded by the National Dairy Council, the Robert H. and Carol L. Deibel Distinguished Graduate Fellowship in Food Safety Research (University of Wisconsin–Madison), and by unrestricted gifts from the industry to the Food Research Institute, University of Wisconsin–Madison.

The H5N1 inactivation work was funded by the New York State Department of Agriculture and Markets (award no. CM04068HM). The US. Food and Drug Administration funded the studies related to the z-score estimation (award no. 1U18FD008488-01).

     

For information regarding the accessibility and usability of this application, view the Accessibility and Usability KB.

Disclaimers

• Temperature must be taken at the coldest point of the system.
• Milk must be stirred/agitated during thermization to ensure each particle is heated.
• Time output is for hold time and does not include integrated lethality for come-up and cool down times.
• Values are valid for bovine milk with typical fat content 5% fat or less. Milk of higher fat content may require greater thermization.
• Data for D- and z-values for Listeria monocytogenes and Shiga-toxin producing E. coli were derived from experiments by Engstrom & Glass 2021, J. Dairy Science.
• Data for D- and z-values for H5N1 were derived from experiments by Nooruzzaman et al., 2025. Nat Commun

The Food Research Institute’s Cheese Thermization Software (the “Software”) is made available at no cost and provided “as is” as an informational reference for cheesemakers in connection with the University of Wisconsin-Madison’s education and outreach missions. The Software may give inaccurate results due to the insertion of inaccurate data by the user, by a technical error within the server at the moment of calculation, or other unforeseen circumstances. Users accept all risk associated with use of the Software, and remain responsible for compliance with all regulatory and other requirements related to their cheesemaking activities, including but not limited to all requirements related to food safety.

THE UNIVERSITY OF WISCONSIN-MADISON EXPRESSLY DISCLAIMS ANY AND ALL WARRANTIES IN CONNECTION WITH THE SOFTWARE, INCLUDING BUT NOT LIMITED TO WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE, WARRANTIES OF MERCHANTABILITY, AND WARRANTIES OF NON-INFRINGEMENT.

By using the Software you acknowledge and agree to the foregoing and waive any and all claims of any kind and description against the Board of Regents of the University of Wisconsin System, its officers, employees and agents, in connection with your use of the Software and any decisions you may make as a result of using the Software.