| Popis: |
Summary A small fermentation system was devised for continuous automatic propagation of dairy cultures. The fermentor is a circulatory, 1-in. diameter, stainless steel pipe assembly of 1,000-ml. capacity, in which skimmilk is continuously and slowly circulated. Acidity is controlled with a pH meter and meter-relay which activates a solenoid valve controlling the skimmilk inflow. The fermentation system has been operated for 12 wk., but not without contamination and undesirable fementations. Successful trials free from contamination have been conducted for 3 wk. These have provided information regarding the throughput rate at various temperatures between 50 and 90° F. At 90° F. the retention time or growth rate was 30 min. The critical pH level was 5.3, below which the rate of growth was reduced. Dairy cultures can be propagated continuously at maximum growth rates without impairment of flavor or activity, with constant temperature and pH (above 5.3 for maximum rate) and in continuous motion. |
