Table 1. Sample Provenance.

suppliera	1	1	1	2	2	2	2	3	4	5	6	7	8
prod. siteb	US1	US2	US2	US3	US4	US5	US6	I1	I2	I3	US7	?	US8
milk classc	N	N	S	S	S	S	S	S	S	S	N	N	N
samplesd	5	10	2	3	3	4	2	2	1	2	2	2	3
proc. typee	L,H	L,M	L,?	L,M	L,M	L,H	M	M	M	M	L,H	?	L
no. of analysesf	30	60	12	18	18	24	12	12	6	12	12	12	18

^aEight suppliers.

^bProduction site per supplier in the United States (US), internationally (I), or unknown (?).

^cN = nonfat dry milk and S = skim milk powder.

^dNumber of samples collected from each production site.

^eProcess type: L = low, M = medium, H = high, or ? = unknown heat.

^fSix subsamples per sample (two subsamples/sample/day for 3 days).