

EFFECT OF STORAGE ON THE VITAMIN A 

 POTENCY OF BUTTER 



The laboratories at the Wisconsin, North 

 Carolina, Minnesota, Ohio, California, and 

 Mississippi Agricultural Experiment Stations 

 investigated the effect of storage on the vitamin 

 A potency of butter. Samples of butter were 

 handled and stored under various practical 

 conditions. The results indicate that both 

 carotene and vitamin A are very stable in butter under the condi- 

 tions tested; that little if any loss of vitamin A potency occurs 

 during the periods that commercial butter is ordinarily stored; 

 and that, insofar as the effect of storage is concerned, one would 

 not expect the average vitamin A potency of the butter sold on 

 the retail markets in this country to be significantly different from 

 the average of the creamery butter produced in the country as a 

 whole. The results from each State on the effect of storage are 

 briefly as follows: 



Wisconsin. — Investigators at the Wisconsin Agricultural Experiment Station 

 stored four 64-pound tubs of butter at —21° to —23° C. The tubs were 

 unparaffined, lined with parchment paper, and closed with wooden lids. 

 There was no change in either the vitamin A or carotene after storage 

 for 8 months. 



They also stored seventy 1 -pound packages of butter in original paper 

 wrappings and cartons for 5 months. Ten of these samples were then 

 analyzed. These samples showed no loss of either vitamin A or carotene. 



North Carolina. — At the North Carolina Agricultural Experiment Station 

 samples of butter collected during August and November, 1943, were analyzed 

 and then stored at 10° F., for 3 months or 6 months. The investigators found 

 no loss of either carotene or vitamin A as a result of storage; as a matter of 

 fact, the carotene values in all cases showed "an embarrassing increase" of 

 from 0.1 to 0.3 microgram per gram. 



Minnesota. — At the Minnesota Agricultural Experiment Station one 10-pound 

 tub of butter was collected from each region each month during the first 

 6 months of 1943. After a sample was taken from each tub for immediate 

 analysis, the tubs were stored at — 10° F., and other samples were subsequently 

 withdrawn and analyzed after storage periods of 3 and 6 months. The average 

 (weighted) carotene and vitamin A content of the 52 tubs of butter was as 

 follows: 



Micrograms per gram of butter 

 Carotene Vitamin A 



Storage period: 



Fresh 2.97 5.16 



3 months 2.97 5.38 



6 months , 2.93 5.50 



These results indicate that the carotene content of the butter was little 

 affected by storage. In the case of the vitamin A content, the Minnesota in- 

 vestigators concluded that the "very disturbing anomalous increases after 

 storage" must be attributed to an uncontrolled error in the experiment. For 



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