22 DAIRYING 



thrown away and the starter ruined by any neglect in this 

 direction. 



The cans, buckets, dippers, stirrers, cloths, covers and every- 

 thing used in the preparation of a starter should be thoroughly 

 steamed after they have been washed and rinsed with clean 

 water. A steaming box or oven may be provided for this pur- 

 pose and the tinware should be heated in it to a boiling tempera- 

 ture for at least one-half hour. An exposure of the starter or 

 of the cans to the air, by leaving them uncovered, or by rinsing 

 the cans with water which has not been boiled, may spoil the 

 work already done, and it is therefore very important that every 

 precaution possible should be taken to prevent the contamina- 

 tion of the pure culture with undesirable bacteria. Even the but- 

 termaker's hands should be rinsed in water which has been 

 boiled and he should also avoid putting his hands inside the 

 cans, pails, etc. After these utensils have been sterilized, the 

 cans used for holding the starter ought to have covers made with 

 overlapping sides that fit outside instead of inside the can walls. 



Bacteria are so numerous and so widely distributed that in 

 starter-making it is safe to assume that they are always growing 

 on anything which has not been previously heated to a suffi- 

 ciently high temperature to destroy them. On account of the 

 susceptibility of a starter to outside contamination, it is always 

 safest to skim off and throw away the top layer of an inch or 

 more.. This often contains some undesirable bacteria that have 

 found their way into the can in spite of all precautions to keep 

 them out. 



General Precautions Regarding Starters. 



556. Strict rules in regard to temperatures and the length 

 of time that the starters must be kept at definite temperatures 

 cannot be safely followed from day to day. The maker must 

 use his judgment in regard to the best conditions necessary for 

 the starter in each case. 



