FIG. 3.

Effect of heat treatment on DNA stability. Cells were incubated at 25°C (A), 55°C (B), 72°C (C), and 100°C (D) for up to 5 days, and DNA was quantified by 5′-nuclease PCR assay after 5 min, 1 h, 6 h, 24 h, and 5 days. The amounts of DNA (copy numbers) and numbers of culturable cells (CFU counts) are given relative to the values before heat treatment. The error bars show standard deviations.