F0 VALUE

F0 VALUE

F0 is the equivalent exposure time at 121.11°C of the actual exposure time at a
variable temperature, calculated for an ideal micro-organism with a temperature
coefficient of destruction equal to 10.

"F0 means the equivalent amount of time, in minutes at 121°C or 250°F, which has been delivered to a product by the sterilization process". For the calculation of it, "a z-value of 10°C or 18°F is assumed; the term z-value means the slope of the thermal death time curve and may be expressed as the number of degrees.... required to bring about a tenfold change in the death rate".

In practice, the knowledge of the temperature values as the continuous function of elapsing time is not available, and F0 is calculated as follows:

Fo = D t log10 (Ta-Tb/Z)

where:

۸ t - Cycle time at a particular temperature
Ta - Actual temperature
Tb - Actual cycle temperature (i.e.110 degree) or base temperature
Z = 10.0 Degree centigrade

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