Studies on the Proteolytic Action of Dairy Lactic Acid Bacteria

Part X. Autolysis of Lactic Acid Bacterial Cells in Asptic Rennet Curd

Abstract

Preparation of aseptic rennet curd was carried out to investigate the autolysis of lactic acid bacterial cells during cheese ripening. The asepsis of these prepared curds was effectively maintained during ripening. No change in DNA content of this aseptic rennet curd was observed during ripening. Aseptically harvested and washed cells of Str. cremoris and L. helveticus, both of which were cultured for 48hr in the liquid media, were sandwiched between aseptic rennet curd. These sandwiched curds were perfectly coated with paraffin wax.
Rapid increase in cell free DNA content of these sandwiched curds was observed during the ripening period of 6_??_12 days at 10°C. It seemed that both kinds of lactic acid bacterial cells sandwiched between the curds began to autolyze during 6_??_12 days ripening and that intracellular substances were released from the autolyzed cells. These autolyzed cells were clearly observed by electron micrography.