FORMS OF STARTERS A. Liquid Culture Most popular and widely used form. The starters are normally preserved in small quantities. Working cultures are maintained with either weekly or daily sub-culturing. Starters can be preserved in liquid form using one of the following two different growth media viz.,Reconstituted skim milk, litmus milk. Reconstitute the Non-fat dry milk which is free from antibiotics to a total solid content of 10-12%. It is sterilized by auto claving at 10-15 psi / 10-15 minutes. Check the sterility by incubating at 30°C for one week. Factors affecting the starter culture activity: 1. The rate of cooling after incubation. 2. Level of acidity at the end of incubation period. 3. The temperature of storage. 4. Duration of storage. B. Frozen, Deep Frozen and Frozen Concentrates 1. Frozen Culture The cultures are frozen to -20°C. Liquid starters (Mother and Feeder cultures) can be preserved for few months. 2. Deep freezing Culture Propag