Table 1 General sample characteristics (n= 178)

Sample		Number (%)	p-valuea
Plants	Meat packing plants	178 (100.0)
Month	January	7 (3.9)	<0.001
	February	9 (5.1)
	March	6 (3.4)
	April	14 (7.9)
	May	15 (8.4)
	June	12 (6.7)
	July	21 (11.8)
	August	18 (10.1)
	September	6 (3.4)
	October	16 (9.0)
	November	22 (12.4)
	December	32 (18.0)
Season	Spring	35 (19.7)	0.040
	Summer	51 (28.7)
	Autumn	44 (24.7)
	Winter	48 (27.0)
Animal	Beef	76 (42.7)	0.917
	Pork	89 (50.0)
	Chicken	13 (7.3)
Product form	Raw material	38 (21.3)	0.496
	Finished product	140 (78.7)

Results are shown as frequencies (%).
^a Indicates that p-value for trend <0.05.