Southern Wisconsin Cheesemakers' and Dairymen's Association / Proceedings of the tenth annual meeting of the Southern Wisconsin Cheesemakers' and Dairymen's Association held at Monroe, Wisconsin, Thurs. and Fri., January 27 and 28, 1910
Hart, T. B.
Variations in the amount of casein in cows' milk and the operation of the casein test, pp. 44-53 PDF (1.9 MB)
SOUTHERN WIS. CHEISEHMAKERS & DAIRYMAEN'S ASS'N. 4') Operating the Casein Test at Cheese Factories. APPARATUS. The Hart casein test is a simple and rapid method of determining the amount of casein in milk. It is based on the use of a centrifuge for separating the casein after its precipitation with dilute acetic sold. The centri uge used is much like a Babcock tester, except that the pockets are deeper and it is geared to run at a higher speed. The test bottle resembles somewhat an inverted Babcock cream test bottle. The complete outfit can be purchased from the dairy supply houses. REAGENTS C h I or o f or m -A high grade of chloroform should be used. This can be obtained at local drug stores at about fifty cents per pound, depending upon the quantity purchased. It is better not to buy over two pounds at a time. When not in use the chloroform bottle should be kept in a cool dark place. A c e t i c A c i d -A 10 per cent acetic acid solution is usually furnished by the supply houses, at 25 cents per quart. If the glacial acetic acid (99)- per cent pure) is pur- chased, at 10 per cent solution is made by diluting 10cc. of the strong acid to 100cc. with clean rain water or condensed steam. Then 25cc. of the 10 per cent acid are diluted to 1000cc. with water. This gives a 0.25 per cent solution, the correct strength for the casein test. The acid bottles should be plainly labeled, in order that acid of wrong strength will not be used. TEMPERATURE. The testing should be done in a room the temperature of which is about 60 degrees or 7') degrees F. The curing room is a good place for the tester; the making room is apt to be too hot in the summer or too cool in the winter. The milk samples should be at a temperature of 65 degrees to 75 degrees F. It may be necessary to warm or cool the samples before testing, depending on the season.
Based on date of publication, this material is presumed to be in the public domain.| For information on re-use, see http://digital.library.wisc.edu/1711.dl/Copyright