Three modes of batch culture of Lactobacillus helveticus were compared: the conventional culture inoculated with 11% (v/v) seed culture and cultures inoculated with 0.1 or 11% (v/v) of a volume fraction of the preceding culture, reactivated first at acidic pH. Culture reuse was useful with low nitrogen supplementation of culture medium (5 g yeast extract l(-1)). Even when the volume of reused culture fraction was minimal (0.1% v/v), a 14% increase in the mean production rate was observed, compared to the conventional mode of batch culture.