For Category 1 Products
Bacteria: No less than 1.0 log reduction for the initial calculated count at 7 days, not less than 3.0 log reduction at 14 days, and no increase from the 14 days’ count at 28 days.
Yeast and Molds: No increase from the initial calculated count at 7, 14, and 28 days.
For Category 2 Products
Bacteria: No less than 2.0 log reduction from the initial calculated count at 14 days, and no increase from the 14 days’ count at 28 days.
Yeast and Molds: No increase from the initial calculated count at 14 and 28 days.
For Category 3 Products
Bacteria: No less than 1.0 log reduction from the initial count at 14 days, and no increase from the 14 days’ count at 28 days.
Yeast and Molds: No increase from the initial calculated count at 14 and 28 days.
For Category 4 Products
Bacteria, Yeast, and Molds: No increase from the initial calculated count at 14 and 28 days.
Note: No increase is defined in the USP <51> method as not more than 0.5 log unit higher than the previous measured value.