Table 5.

 Summary of risk factors for Listeria monocytogenes shedding on pig farms reported in two studies

	Risk factor of presence of Listeria monocytogenes		OR [90%CI]	Reference
Biosecurity	Change room	Lack of change room at the entrance of facilities	7.7 [1.2–49.7]	Beloeil et al., 2003a
	Boot disinfection	Frequency of boot disinfection inferior to once a week	4.7 [1.4–15.6]	Beloeil et al., 2003a
	‘Empty and clean’ period	An ‘empty and clean’ period of one day or less between two fattening batches	3.5 [1.4–11.8]	Beloeil et al., 2003a
Feed	Wet feed	L. monocytogenes was isolated from 19.3% of the 57 wet feed batches studied versus 5.9% of the 36 dry feed batches	4.4 [1.1–17.2]	Beloeil et al., 2003a
		Listeria spp. was isolated from 93% of the 27 wet fed pens studied versus 50% of 20 dry fed pens	12.5* [7.0–22.4]	Beloeil et al., 2003b
	Cleaning of pipelines used for wet feed	Pipeline cleaning and disinfection	8.4* [4.7–15.1]	Beloeil et al., 2003a

*Calculated OR from published data.