FIG. 2.

Heat resistance of E. coli strains. Cells grown to the stationary phase in TSB were diluted 1:100 in fresh TSB (10⁷ CFU · ml⁻¹) and heated at 52°C (A) or 57°C (B). Each curve shows the average values obtained from at least two independent experiments. The mean standard deviation, shown for each curve, varied between 0.15 and 0.7. The strains used were E. coli O157 C9490 (●), 30-2C4 (□), NCTC 12079 (▴), W2-2 (○), and H1071 (■) and E. coli O124 NCTC 8003 (▵).