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Lethality Set-Point Calculator
Chamber spread is the reason two dryers running the same recipe do not produce the same product. Enter the mean and the standard deviation you measured across your chamber and this calculator returns the set point that keeps the cold spots above your lethality temperature.
| Sigma level | Units per million not reaching lethality temperature |
|---|---|
| 3 sigma | 33,400 |
| 4 sigma | 6,200 |
| 5 sigma | 230 |
| 6 sigma | 1.7 |
Where the numbers come from, and what they are not
The set-point method and the units-per-million column are published extension guidance for small-scale jerky dehydrators, which sets the set point at the measured mean plus a multiple of the measured standard deviation and asks for at least twelve temperature readings taken at different locations in the chamber. Shengtu supplies the chamber, the controls and the pre-shipment stability evidence. Shengtu does not supply, validate or certify a lethality process: the validated process belongs to your process authority and your regulator, and this calculator is a planning aid, not a validation record.

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