356 Milk and Its Products 



6. Incubate at about 60 to 75 F. The first inoculation from the 

 commercial culture should be incubated at about 70 to 85 F. The 

 small inoculations require higher temperatures than the large inocu- 

 lations. By experience an operator can soon learn what inoculation 

 and temperature to use to ripen his starter in a given time. Usually a 

 6 to 8 per cent inoculation will ripen a starter in twelve hours at about 

 65 F. The temperature must be fairly constant. 



7. The starter is ripe when a curd forms. This curd should be soft 

 and like custard in appearance. It should not be hard and firm. 



8. After the starter is ripe, hold it at 50 F. or a few degrees lower 

 until time to use. For best results a starter should not be held longer 

 than a few hours. However, it may be held two or three days and not 

 be badly over-ripened. Do not shake the starter before putting it in 

 storage. 



9. Upon examination the curd should be smooth and compact, 

 without gas pockets. Gas shows the presence of undesirable bacteria. 

 A hard, lumpy curd, whey, and high acid show the over-ripe condition, 

 which is very undesirable. After the condition of the curd is noted, 

 shake well to break it into a smooth, lumpless condition. Shake with 

 a rotary motion, being careful not to touch the cap for fear of con- 

 tamination. Now smell and taste it, but never from the starter con- 

 tainer. Always pour some of the curd into a spoon or cup, and then 

 replace the cover immediately. After smelling, it is best to put at least 

 a teaspoonful into the mouth. Seek for a desirable, clean, mild, acid 

 flavor. The first propagation is likely to be somewhat disagreeable 

 because of the presence of some of the original medium. 



GENERAL DIRECTIONS 



In a creamery or a large dairy it is necessary to carry more than a 

 pint or a quart of starter. Along with the mother starter a second 

 starter of ten to fifty pounds may be carried. After the mother starter 

 in the glass container is inoculated, the remainder of the previous day's 

 mother starter is poured into the second starter, and the cream is inocu- 

 lated from the second starter. In large creameries, third and fourth 

 starters are carried. Care should be taken in pasteurization not to cook 

 the milk in these large amounts. In the mother starter this makes lit- 

 tle difference. 



It is necessary to use a larger inoculation from starter to cream 

 than from starter to starter, because the seed bed is not so well pre- 

 pared. The inoculation of the cream may vary from 8 to 50 per cent. 



