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Calculator for determining the lethality (F, B* values) and chemical changes (C* value) for UHT processes using the trapezoid and Simpson's rules
The calculator calculates the the F, B* and C* values in heated products using pasted time-temperature values or keyboard inputs. Users can enter their own data for reference temperature and Z value for determination of the F value of their choice;121.1°C and 10°C respectively for F0. Constants for B* and C* are pre-programmed.
The individual lethality, B and C values are integrated to give F, B* and C* using the industry standard method, the trapezoid rule,*and compared with a more accurate method of numerical integration, Simpson's 1/3 and 3/8 rules. This gives users a unique resource to see the differences in accuracy obtained by using Simpson's rules. A graph of lethality versus time is also displayed.
To use first add your reference temperature and Z value in the boxes above. Next select time units, seconds for UHT processing, minutes for other thermal processes. Thousands of individual time and temperature values can be pasted. Once added, press the generate table command and then the calculate button. The outputs reflect the differences in numerical integration undertaken using the trapezoid and Simpson's rules. Note I have configured the calculator to require a minimum of 4 time-temperature data sets otherwise an error message will be given.
A similar Excel spreadsheet can be downloaded at https://www.dairyscience.info/index.php/thermal-processing/334-download-spreadsheets.html .
How to cite this article
Mullan, W.M.A. (2018) [On-line] Available from: Accessed: