MILK TESTING 27 



frozen or partially frozen, milk is not in a condition 

 to sample, but should be allowed to thaw and then be 

 thoroughly mixed. 



26. Cleaning Glassware. — In order to secure the 

 best results, the test bottles and all of the glassware 

 used in testing milk should be kept clean. The test 

 bottles should be emptied before the fat becomes 

 cold and hard. By shaking the test bottle, the sedi- 

 ment of lime sulphate or gypsum is removed with 

 the acid mixture. The test bottles can be left to 

 drain on the drain board placed over the acid waste 

 jar. A drain board with holes large enough to receive 

 the neck of the test bottle will be found very useful 

 in handling a large number of test bottles. The test 

 bottles should be rinsed while still hot with warm 

 water and after draining this should be followed by 

 a second rinsing with hot water. A small brush will 

 be found usefid in keeping the necks of the boltles 

 clean. Occasionally it will be net^essary to give tlie 

 test bottles a bath in hot water eontaining a little 

 alkali, sal soda, Babbitt's potash, gold dust, or any 

 similar material dissolved in the water in small 

 amounts. A small copper tank large enough to re- 

 ceive a rack containing twelve to twenty-four test 

 bottles so they may be completely immersed will en- 

 able the creamery or factory man to keep his test 

 bottles in a good condition. 



27. Water used in Milk Testing. — Hard waters 

 containing large amounts of lime or alkaline salts 

 are not suitable for use in milk testing. Rain water 



