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The Results of Deaeration on the Oxygen, Vitamin C, and the Oxidized Flavors of Milk

Department of Dairy Industry, Cornell University, Ithaca, New York

ABSTRACT

1. The oxygen of milk may vary from 0, or near that point in the udder, to about 11 milligrams per liter in the bottle in undeaerated milk.
   
2. An intermittent deaerator was used in a series of experiments that extended through 3 periods in 3 years, or a total of 57 weeks. The vitamin C, in the milk in these series of analyses, dropped from 17.9 milligrams per liter in the fresh milk to 16.42 milligrams per liter in the deaerated milk at the end of 7 days, and to 7.68 milligrams per liter in the undeaerated milk during the same period.
   
3. The flavor of the milk that was deaerated in the intermittent unit was "excellent" when fresh. At the end of 7 days the deaerated milk was "good," whereas the undeaerated milk was "poor" due to the oxidized flavors.
   
4. A continuous deaerator has been in daily operation by largely unskilled operators for 45 months. Data obtained during the first thirty month's operation are reported. Forty-nine samples out of 362 analyses on as many days, contained no oxygen, and many others were near that point.
   
5. During the 30 months of the operation of the continuous deaerator the average of 250 analyses of fresh milk was 17.19 milligrams of vitamin C per liter. The "in-bottom filled," the "commercially filled," and the "air reincorporated" samples of 7 days' old milk averaged 15.26, 13.03, and 6.08 milligrams of vitamin C per liter, respectively.
   
6. The 250 comparisons made during the 30 months of daily operation of the continuous deaerator show that the flavor of the fresh milk, in general, was "excellent," and at the age of 7 days the "in-bottom filled," the "commercially filled," and the "air reincorporated" milks were good, fair, and poor, respectively.
   
7. The deaerators used in this study were constructed to take the oxygen out of milk in order to prevent the development of the oxidized flavors. The opinions of several reputable judges of milk show that they accomplished the purpose for which they were made. An added advantage of importance is the preservation of substantial amounts of vitamin C.