USE OF BACILLUS BULGARICUS IN CHEESE STARTERS. 15 



PREPARING THE STARTER. 



The starter can is first sterilized with steam or boiling water. The 

 pure culture is then placed in the lower tank and the block-tin plug 

 screwed down in place. The upper tank is then filled with boiling 

 whey and the cork and thermometer inserted. The whey is allowed 

 to stand in the upper tank until cooled to about 104° F. if Bacillus 

 hulgaricus starter is used (in case the common lactic-acid type is used, 

 the temperature should be 77° F.). The block-tin plug is then raised 

 by means of the brass pipe to let the whey pass to the lower tank, 

 where it is inoculated with the bacteria in the pure culture previously 

 placed there. The block-tin plug is then replaced. The next day 

 this starter is drawn off and the upper tank refilled with boiling 

 whey, this operation being repeated from day to day. It is desirable 

 to fill the upper chamber with the boiling whey in order that the 

 chamber may be completely sterilized and all yeast cells destroyed. 

 Milk can not be used in this apparatus, because the coagulated casein 

 might clog the small pipe at the bottom of the lower chamber. 



It would appear probable that the starter-can described above 

 might be used for carrying mother starters for all dairy purposes, 

 if whey is used. It could be made in any size to suit, and it might 

 be used for carrying the entire starter. Where used for a mother 

 starter in a Swiss-cheese factory, the upper chamber should hold 

 almost a pint and the lower chamber 1^ pints. If it is used for 

 carrying the entire starter, the upper chamber should hold 5 gallons 

 and the lower chamber slightly more. For a Cheddar-cheese factory 

 a can three times as large as for a Swiss-cheese factory might be 

 needed. As already indicated, the mother starter for which the can 

 is designed is a small starter carried under conditions to insure its 

 remaining pure. The mother starter is added to the larger starter 

 intended for the milk. 



To prepare the starter where this mother-starter can is used the 

 whey used should be first heated by setting in boiling water and 

 holding for not less than 15 minutes at about 200° F. It should then 

 be cooled to 100° F. and 2 to 5 per cent of the mother starter added. 

 The whey with the rennet added should then be carried at 100° F. 

 for 24 hours, when it should have more than 1 per cent of acid. If 

 the mother starter becomes contaminated with yeast, which may 

 happen if whey from some other factory or any other means than a 

 pure culture is used to renew the starter, the can should be drained 

 and filled with boiling water two or three times successively to kill 

 the yeast present and another start made with the culture or the 

 whey, as the case may be. 



A growth of Mycoderma, which shows itself on the starter as a 

 thin white film, is desirable for improving the efficiency of the starter. 



