TABLE 1.

Membrane fatty acids of E. coli O157 strains

Fatty acid type	% of total area ina:
	Strain C9490	Strain NCTC 12079	Strain H1071
12:0	5.2	7.8	7.2
14:0	17.6	17.3	13.9
14:0-OH	9.3	20.6	17.6
16:0	38.8	31	34.2
17 cyclopropane	19.5	16.3	17.8
19 cyclopropane	8.8	4.9	6.1
Total cyclopropane	28.2	21.2	23.8

^aData are the averages of four values. The standard deviations varied between 0.1 and 1%.