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Single-service paper containers for milk are being used more widely each year. The effect of sunlight on the flavor of milk stored in such containers has not, however, been studied extensively j and few data are available in the literature on this subject. Doan and Myers (1936) studied the influence of sunlight on milk exposed in clear glass, in opaque glass, and in one brand of paper container (Sealcone), The reduction time of sterilized methylene blue milk in such containers was used as an index of the amount of light penetrating the container. With skim milk they found the reduction times were identical, whereas with whole milk the opaque glass gave complete protection and the paper container partial protection. With clear glass the reduction time was greatly decreased. The effect on milk flavor was that the milk exposed in paper containers became slightly tallowy after 30 minutes in the sunlight and definitely tallowy after 50 minutes. The milk in the clear glass bottles had a slight burnt flavor after 20 minutes and a burnt, slightly tallowy flavor after 30 minutes. Tracy (1938), studying another type of bottle (Pure-pak), concluded, "While milk stored in paper containers will acquire the 'sunshine flavor,? the effect of the sun is not nearly so serious as it is in the case of the milk in glass bottles." He gave no data, however. Guthrie, Hand, and Sharp (1939) investigated the stability of added ascorbic acid in milk exposed to sunlight in one type of paper container. "Only a slight decrease in ascorbic acid occurred," they state, "in the samples held in paper bottles. This indicated that the paper bottle protected appreciably the milk from the accelerative effect of sunlight on the destruction of ascorbic acid in the presence of oxygen. I n addition it was observed that the paper bottle, to some extent, protected the milk against the development of the burnt, or oily, or sunlight flavor. " REVIEW O F LITERATURE EXPERIMENTAL PROCEDUREXource of M i l k : The milk used f o r determining the effect of sunlight upon rate of ascorbic acid oxidation and upon milk flavor was 153

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