TABLE 4.

E. coli O157 isolate matches

Lota	No. of postharvest matching preharvestb	Total no. of postharvest samplesc	No. of postevisceration matching preeviscerationd	Total no. of carcass samplese
A1-1	13	13	3	3
A1-2
A1-3	5	9
A2-1
A2-2
A2-3
A2-4
B1-1
B1-2
B1-3			1	2
B1-4	4	7
B2-1	11	12	4	4
B2-2	16	17	5	7
B2-3	5	7	0	1
B2-4	1	3
C1-1	0	8	1	2
C1-2	28	29	10	11
C1-3	5	14	2	6
C1-4	8	14	1	5
C2-1	3	5	1	1
C2-2	1	4	0	1
C2-3			0	1
C2-4	9	15	1	2
D1-1
D1-2
D1-3
D1-4
D2-1	2	2
D2-2	9	13	3	3
D2-3	0	4

^aFor lot designations, the letter indicates the plant, the first number indicates the trip, and the last number indicates the lot. Lots indicated in boldface type included preharvest isolates unlike any postharvest isolates. 

^bThe number of postharvest samples with isolates of the same type as preharvest sample isolates. Only the 17 lots including at least two preharvest and two postharvest E. coli O157 positive samples were analyzed. 

^cThe total number of postharvest samples testing E. coli O157 positive. Only the 17 lots including at least two preharvest and two postharvest E. coli O157 positive samples were included. 

^dThe number of carcasses with matching postevisceration and preevisceration isolates. Only lots with carcasses testing positive at both sites were included. 

^eThe total number of carcasses testing E. coli O157 positive both preevisceration and postevisceration. Only lots with carcasses testing positive at both sites were included.