CHANGES IN FRESH BEEP DUEING COLD STOEAGE. 7 



Wright (1912) made a chemical and bacteriological study of fresh 

 and frozen New Zealand lamb and mutton. Carcasses of each class 

 of animals were stored at 2° to 19° F. for periods ranging from T 

 to 160 days. Samples were examined chemically and bacteriologi- 

 cally in the fresh condition and at intervals throughout the course 

 of the experiment. The results of these experiments indicate the 

 following changes in the lamb and mutton stored for 160 days at 

 2° to 19° F. : Loss of moisture amounting to from 2 to 3 per cent; 

 an increase in proteose, peptone, and meat-base nitrogen ; and no ap- 

 preciable change in ammoniacal nitrogen or in the free acidity of 

 the fat. The changes in chemical composition were ascribed to 

 enzym action. The bacterial condition of the frozen meat remained 

 the same as that of tlie fresh product. When freezing and subse- 

 quent thawing were carried on gradually, there was no alteration 

 in the structure of the tissue. The nutritive value of the lamb and 

 mutton was not affected by freezing and storage. 



Ascoli and Silvestri (1913) carried on a series of experiments con- 

 cerning the relative properties of fresh and frozen beef. Fresh, 

 local beef (Italian), and frozen Australian and Argentine beef that 

 had been held in cold storage about two months were used for the 

 investigation. The following ground was covered in the studies with 

 each class of meat : Chemical composition, digestibility in vitro, action 

 on gastric secretion, digestibility with human subject, histological and 

 autolytic changes. Certain changes were noted in the frozen as com- 

 pared with the fresh meat, viz, a change in color, an increase in soluble 

 protein which exuded in the form of a reddish fluid when the meat 

 was thawed, the development of a peculiar taste, and a decrease in 

 the aromatic odor of the broth. The changes were more apparent 

 in the fat than in the muscular tissue. The changes noted were 

 ascribed to the action of enzyms. The authors concluded that frozen 

 meats may be regarded as a wholesome food product and may be 

 eaten without injury. 



PURPOSE AND PLAN OF PRESENT INVESTIGATION, 



Purpose of investigation. — This investigation was undertaken with 

 the. following objects in view: (1) To study the changes which take 

 place in fresh beef stored at temperatures above freezing, with special 

 reference to the effect of such changes upon the wholesomencss of 

 the product; (2) to determine the causes of the changes which take 

 place in fresh beef held in cold storage under the above conditions; 

 (:'.) tf) determine the length of time that fresh beef can be held in 

 cold stoi'age at tem[)eratures above freezing and remain in whole- 

 some condition, with sp(!cial reference to the ellect of various factors 

 upon the length of the storage period. 



