Investigation of the Distribution of Salmonella within an Integrated Pig Breeding and Production Organisation in the United Kingdom

Table 4

Extent of Salmonella infection on study farms.

Percent positive samples	Number of farms in category
	S. Typhimurium (STM)	Non-STM Salmonella
0*	70 (43.5%)	97 (60.2%)
5–25	68 (42.2%)	51 (31.7%)
30–50	13 (8.1%)	10 (6.2%)
55–75	8 (5.0%)	1 (0.6%)
80–100	2 (1.2%)	2 (1.2%)

∗Values in this row indicate the number (and percentage) of farms yielding no isolates of either STM or non-STM Salmonella. Fifty out of the 161 farms did not yield any Salmonella isolates at all.