TABLE 1.

Prevalence of Escherichia coli O157:H7 in feces, gallbladder tissue, and gallbladder swabs of beef cattle at slaughter

Sample date (day-mo-yr)	No. of cattle sampled	No. (%) of cattle positive
		Feces	Gallbladder mucosal swab	Gallbladder mucosal tissue
23-May-05	79	0	0	0
24-May-05	97	0	0	0
31-May-05	83	4 (4.8)	0	0
1-Jun-05	40	5 (12.5)	0	0
7-Jun-05	95	14 (14.7)	1 (1.1)	2 (2.1)
14-Jun-05	114	2 (1.8)	0	1 (0.9)
28-Jun-05	125	1 (0.8)	0	0
5-Jul-05	55	9 (16.4)	0	0
7-Jul-05	97	15 (15.5)	0	0
21-Jul-05	100	5 (5.0)	0	0
25-Jul-05	48	11 (22.9)	0	1 (2.08)
Total	933	66 (7.1)	1 (0.1)	4 (0.4)