FIG. 3.

Pairwise variations (V_{n/n + 1}) for all the samples during growth in milk and in cheese (two replicates). Pairwise variations between every combination of sequential normalization factors were calculated to determine the minimum number of housekeeping genes required for accurate normalization in the different samples. The cutoff value, below which the inclusion of an additional reference gene does not result in a significant improvement of normalization, was set at 0.15.