Thermal Process (D, z & F Values)

New

Log reductions and process time from the D-value (a 12D cook, say), and D at another temperature from the z-value — sterilisation and pasteurisation

This tool runs entirely in your browser — no file or data is sent to any server.

Enter the values

What to work out

D-value (at the reference temperature)

min

Log reductions wanted (12 for a 12D process)

Result

Time needed (F)

2.52min

This is the equivalent time at the reference temperature; the slower heating inside a can or pack (heat penetration) has to be worked out separately.

Working

Formulas

Assumptions

First-order (log-linear) microbial death is assumed.
D and z belong to a particular organism and food — take them from your textbook or test data; the starting values are only an example.

Sources: P. J. Fellows, Food Processing Technology: Principles and Practice · The canning industry's 12D concept (C. botulinum)

Related tools