An experimental continuous-culture unit for the production of frozen concentrated cheese starters.

Abstract

SummaryEquipment and methods are described for the production, on the laboratory scale, of frozen concentrated cheese starters. A single-stage Porton-type fermenter with a working volume of 3–5 l was used for the continuous culture of theStreptococcus lactisandStr. cremorisstarter strains. The cells grown in a trypsin-digested cheese-whey or trypsin-digested skim-milk, both containing autolysed yeast, were harvested with a Sharples laboratory super-centrifuge, resuspended in skim-milk and layer-frozen in liquid N2. The frozen culture was crushed to a granular free-flowing form facilitating direct addition to and ready dispersion in cheese milk. The cultures were stored at −196°C.