520 MANUAL OF MILK PRODUCTS 



infrequently picked up at the points of ice cream manufacture. 

 Hot water and human labor are both expensive ; yet both are 

 essential to cleanliness. It is entirely probable that some, at 

 least, of the apparent cases of ptomaine poisoning ascribed to old 

 re-frozen ice cream were due to the action of putrefactive organ- 

 isms introduced by the stale, greasy, arid half cold water used in 

 washing the cans. To those who know milk and its handling, 

 there is no flavor more disgusting. A cream which has started 

 to sour may under stress be used, either by the use of sweet 

 cream or by first reducing its acidity to that of normal cream, 

 say to about 0.20 per cent acid, using either bicarbonate of soda 

 (baking soda, saleratus), or viscogen (sucrate of lime). 1 Care 

 must be taken, however, not to add too much, lest the cream be 

 made alkaline and the taste bitter. 

 Fat-content. 



Ice creams, or ice milks, as the case might be, were made, 

 using varying grades of material testing 43 per cent, 37 per cent, 

 30 per cent, 25 per cent, 22 per cent, 18 per cent, 12 per cent 

 (cream), 8 per cent, 4 per cent (milk), and per cent (skim- 

 milk) . The rich 43 per cent cream afforded a poor yield, swell- 

 ing but little. It had a firm body, but was so buttery and rich 

 in flavor that it did not approve itself to a single one of the 

 several dozen tasters, whose verdicts in this and other trials 

 mentioned all through this bulletin were always given in entire 

 ignorance of the identities of the creams they were sampling. 

 The 37 per cent and the 30 per cent creams met with somewhat 

 more favor and gave better results ; but they were still too rich. 

 The cream testing 25 per cent fat (before the sugar was added) 

 was the choice where the swell was very moderate ; but when 

 the several lots were frozen slowly and thoroughly whipped, 

 the consequent incorporation of air so increased the apparent 

 richness of the cream that the 22 per cent goods was largely 



1 Wis. Sta. Bui. 41 (1894). 



