Table 1.

Protein yields and enzymatic activities in phosphate buffered saline without freezing and with each of four freeze/thaw regimes^*

	No freeze	Any freeze- thaw	Fast freeze Slow thaw	Fast freeze Fast thaw	Slow freeze Slow thaw	Slow freeze Fast thaw
Analyte		Means (SEM), P-values compared to no freeze
Total protein	1.5 (0.04)	2.38 (0.05) P=0.0001	2.45 (1.73) P= 0.01	2.02 (0.07) P= 0.13	2.54 (0.11) P= 0.01	2.53 (0.08) P= 0.01
β-Glucuronidase activity†	2.47 (0.05)	2.61 (0.04) P=0.12	2.31 (0.12) P= 0.59	2.82 (0.01) P= 0.06	2.63 (0.05) P= 0.64	2.70 (0.03) P= 0.25
β-Glucosidase activity†	3.57 (0.02)	6.16 (0.09) P=0.0001	6.06 (0.2) P= 0.0002	6.49 (0.02) P= 0.0001	6.48 (0.2) P= 0.0001	5.60 (0.01) P= 0.0005

^*Fast and slow freezing and thawing conditions are described in detail in Supplemental Materials. Means and standard error of the means (SEM) were calculated from triplicate measurements in the duplicate fecal subsamples. The P-values that compares each freezing condition with no freeze are from unpaired t-tests with 2 degrees of freedom, because there are n=2 fecal subsamples for each freeze/thaw condition.

^†Enzymatic activity expressed in IU/100mg input protein.