Effect of time on the relative abundances of phylum and family level 16S rRNA sequences obtained from control and glucose treatments. Number of sequences for each treatment: preincubation, 78,847; 10-h control, 107,853; 10-h glucose, 144,612; 20-h control, 98,655; 20-h glucose, 155,353; 30-h control, 118,099; 30-h glucose, 159,689.