The microbial growth curve and the lag phase

The growth curve shows the count of living cells changing through four phases. Temperature raises the growth rate and shortens the lag time, and lag is not the same in every product.

11 November 2024Updated 28 September 2026

Short answer

The microbial growth curve shows the count of living cells passing through adaptation (lag), rapid growth, a plateau and decline. Temperature raises the growth rate and shortens lag, so even a short warm spell brings the curve forward. Lag time differs by product and organism, so the product's own count data is used rather than a ready-made duration.

The microbial growth curve shows the count of living cells changing through four phases: adaptation (lag), rapid growth, a plateau and decline. Temperature raises the growth rate and shortens the lag time.

In one study (Foods, 2026) fermented soybean tofu was followed through two distribution patterns swinging between 4 and 20 °C. In the e-commerce pattern, which met 20 °C, the total viable count reached 5 lg CFU/g on day 17; in the supermarket pattern it took until day 27.

Lag is not seen in every product. On chicken wings (Poultry Science, 2026) the product's own bacteria showed no lag or a negligible one, while Salmonella added for the trial showed lag at 20 °C and declined at 4 and 10 °C.

So no ready-made lag duration is taken: a prediction rests on the product's own counts, its starting load and an unbroken temperature record. Without a record there is no curve, and only the date on the label remains.