Fig. 1

Time profile of pH (X), nisin activity (log AU/mL; solid circle), microbial growth in colony-forming units (log CFU/mL; solid square), lactic acid (mg/mL; solid triangle) in batch cultivations of Lactococcus lactis in diluted skimmed milk in which the pH is uncontrolled, with varied agitation and airflow rates. Culture conditions were: a 100 rpm, no airflow rate; b 100 rpm, 0.5 L/min; c 200 rpm, no airflow rate; d 200 rpm, 0.5 L/min; e 200 rpm, 1 L/min; f 200 rpm, 2 L/min