FIG. 3.

16S rRNA gene microarray quantification of total cell and free bacterial DNA in Lactococcus lactis subsp. lactis INF L2 (a), Propionibacterium acidipropionici ATCC 4965 (b), P. freudenreichii ISU P59 (c), P. jensenii INF P303 (d), a mixed sample of the above-mentioned strains (e), and a coculture of the above-mentioned propionibacteria (f). The total bacterial DNA content was calculated as previously described (44). The 10⁻⁷ dilution of the competitor corresponds to approximately 10⁷ DNA copies per ml in the original sample. The error bars for all samples indicate standard deviations for two or three independent quantifications. *, no parallels are available; d, days; we, weeks.