Why do sterilisation results differ even at the same temperature of 121°C? — In the food processing industry, many companies hold a common misconception regarding high-temperature sterilisation:
“If a product is sterilised at 121°C, it must be safe.” However, in actual production, the following situation frequently arises: even when sterilised at the same temperature of 121°C, some products have a shelf life of over 12 months, whilst others develop issues such as bag swelling, rancidity or even microbial contamination within a few weeks.
Why does this occur? The answer lies not merely in temperature, but in a crucial parameter in food sterilisation: the F₀ value.
Why do sterilisation results differ even at the same 121°C?
Temperature is merely one factor among the sterilisation conditions. For microorganisms, what truly determines the extent of their destruction is:
the combined effect of temperature and time.
| Product A |
121°C for 10 minutes |
| Product B |
121°C for 30 minutes |
Although both products reach the same maximum temperature, the resulting sterilisation effect is entirely different.
The reason is that Product B achieves a higher thermal lethality, capable of killing more heat-resistant microorganisms. Therefore, in the food industry, the effectiveness of sterilisation cannot be assessed by temperature alone, but rather by the F₀ value.
What is the F₀ value?
The F₀ value (Sterilisation Value) is an internationally recognised indicator of the intensity of thermal sterilisation.
It is defined as the time (in minutes) required to achieve an equivalent sterilising effect on microorganisms at 121.1°C.
The higher the F₀ value, the greater the sterilising intensity.
| F_0=3 | indicates an effect equivalent to continuous sterilisation at 121.1°C for 3 minutes. |
|
F_0=8 |
indicates an effect equivalent to continuous sterilisation at 121.1°C for 8 minutes. |
Post time: Jun-08-2026