PT  - JOURNAL ARTICLE
AU  - PFLUG, I. J.
TI  - Discussion of the Z-Value to Use in Calculating the F<sub>0</sub>-Value for High-temperature Sterilization Processes
DP  - 1996 Jan 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - 51--54
VI  - 50
IP  - 1
4099  - http://journal.pda.org/content/50/1/51.short
4100  - http://journal.pda.org/content/50/1/51.full
SO  - PDA J Pharm Sci Technol1996 Jan 01; 50
AB  - The appropriate z-value to use in integrating heat process time-temperature data in the temperature range of 120.0–140.0°C (248.0–284.0°F) is discussed. We conclude that for control of Clostridium botulinum there is little risk in extrapolating a public health F0-value for C. botulinum to temperatures in the 132.0–138.0°C (270.0–280.0°F) range using a z-value of 10.0°C (18.0°F). It would seem prudent, at this time, when extrapolating data to conditions in the 132.0–138.0°C (270.0–280.0°F) range, that as a starting point an F0-value of 3.0 minutes be used as the minimum public health process. A design z-value of 10.0°C (18.0°F) is appropriate for Clostridium sporogenes to temperatures of 140.0°C (284.0°F). To control thermophilic microorganisms such as Bacillus stearothermophilus and Bacillus coagulans with processes at temperatures from 120.0–140.0°C (248.0– 284.0°F), the effective z-value will be in the range of 7.0–8.0°C (12.6–14.4°F) instead of 10.0°C (18.0°F). This means that when we design and calculate processes at temperatures from 120.0–140.0°C (248.0–284.0°F), using a z-value of 10.0°C (18.0°F), the lethal effect against these organisms will be much larger than indicated by the F0-value of the process.