Influence of rennet on growth and autolysis as determined by measurement of total cell bacterial DNA (a), free DNA (b), A600 (c), and CFU/ml (d) for Lactococcus lactis subsp. lactis INF L2. Symbols: ⋄, sample without rennet; ▪, rennet-treated sample. The error bars for all samples indicate standard deviations for at least three independent quantifications.