F₀ value

The equivalent sterilisation time in minutes at 121.1 °C delivered by a heat process, calculated using a z-value of 10 °C. F₀ adds up the lethality of the whole cycle, including heating and cooling, converted to time at 121.1 °C. It allows cycles at different temperatures to be compared. Overkill cycles often target an F₀ of at least 15 minutes, while heat-sensitive products may use a lower F₀ justified by low bioburden.