TABLE 4.

Survival of E. coli ATCC 25922 cells to a lethal treatment following prior exposure to a sublethal treatment^a

Cell category	Cell count (log10 CFU/ml) for:
	Exponentially growing cellsc	Sublethal treatmentb		Lethal treatment
		After treatment (55°C; 105 min; F7010 = 3 min)	After recuperation (37°C [12 h])	After treatment (60°C; 50 min; F7010 = 5 min)	After recuperation (37°C [24 h])
Cells exposed to sublethal heating	8.03	<0.7	7.06	<0.7	7.36
Control cells (not exposed to sublethal heating)d	8.20	NAe	NA	<0.7	<0.7

^aLethal treatment was F₇₀¹⁰ = 5 min, performed at 60°C. The experiment was repeated three times.

^bHeating conditions that provide a DnaK concentration of 12,347 ± 2,363 and 76,786 ± 25,230 molecules/cell after treatment and 12 h of recuperation at 37°C, respectively (Table 3).

^cIncubation of cells at 37°C until an OD₆₀₀ of 0.5 was reached.

^dOptimal growth conditions (37°C; OD₆₀₀ = 0.5) that provide a DnaK concentration of 38,500 ± 6,056 molecules/cell (Table 2).

^eNA, not applicable.