How to Use the Sterilization Process Calculator
For Lethal Rate (L), the formula given is: L = 10^((T-Tref)/z)
Where:
- T = Temperature of the item being heated
- Tref = Reference temperature
- z = z-value of the challenge organism (or 10°C if not known)
The document provides an example calculation: For a BI system with z-value of 10°C, when comparing 120°C vs 121°C: L = 10^((120-121)/10) = 10^(-0.1) = 0.79
This means one minute at 120°C is equivalent to 0.79 minutes at 121°C in terms of lethality.
For F-physical (Fphys), it’s calculated as: Fphys = d∑(L)
Where:
- d = the time increment between each temperature reading
- L = the lethal rate calculated for each temperature reading
This is essentially the integration of lethal rates throughout the process, calculated using the Trapezoidal model by summing up all the lethal rate values multiplied by their time increments.
This Sterilization Process Calculator helps you simulate and visualize the sterilization process, including temperature profiles, lethality rates, and accumulated F₀ values. Follow these steps to use it effectively:
Set the Temperature Setpoint (°C)
- Enter the desired sterilization temperature (default is 121°C) in the “Temperature Setpoint” input field.
Set the Hold Duration (minutes)
- Input the duration for which the sterilization process should hold at the set temperature (default is 15 minutes).
View the Total F₀ Value
- The total F₀ value, which measures the accumulated lethality of the process, is displayed below the input fields. This value updates automatically when you adjust the setpoint or duration.
Explore the Temperature Profile
- The temperature profile chart shows how the temperature changes over time, including ramp-up, holding, and ramp-down phases.
Explore the Accumulated F₀ Profile
- The accumulated F₀ chart displays how the lethality value accumulates throughout the sterilization process.
View the Detailed Table
- Click the “Process Calculations” button to toggle a detailed table of time, temperature, lethality rate, and accumulated F₀ values.
This tool is ideal for professionals or students in food processing, sterilization, or pharmaceutical industries to understand how temperature and time affect the sterilization process.
If you have any questions or need further clarification, leave a comment below the blog post!
