CHANGES IN FRESH BEEF DURING COLD STORAGE, 99 



tures above freezing, it is clearly impracticable to attempt to insure 

 the wholesomeness of the product merely by limiting the duration of 

 storage. The wholesomeness of cold-stored beef must be judged by 

 other considerations besides the length of time that the product has 

 been held in cold storage. 



GENERAL SUMMARY. 



The chemical changes that took place in the muscular tissue of 

 beef held in cold storage at temperatures above freezing for periods 

 ranging from 14 to 177 days consisted chiefly in increases in acidity ; 

 in proteose, noncoagiilable, amino, and ammoniacal nitrogen ; and in 

 soluble inorganic phosphorus ; while decreases occurred in coagulable 

 nitrogen and in soluble organic phosphorus. On the whole these 

 changes were of a progressive nature. The chemical changes that 

 took place in the fatty tissues of the beef consisted chiefly in marked 

 increases in the acidity of the kidney and external fats. 



On the whole the chemical changes that took place in the muscular 

 tissue of the beef during storage were similar in nature to but less 

 in extent than those that were caused by enzymatic action when lean 

 beef was autolyzed under aseptic conditions for periods ranging 

 from 7 to 100 days. 



The chemical changes that took place in the muscular tissue of the 

 beef during storage were without appreciable effect either upon the 

 nutritive value or the wholesomeness of the edible portions of the 

 product ; but the changes that took place in the kidney fat and exter- 

 nal fatty tissue after the longer periods of storage rendered them 

 unsuitable for human consumption. 



The bacteria and molds which grew on the surface of the cold- 

 stored meats did not penetrate the muscular tissue to any great 

 depth. The increased tenderness noticed in the cold-stored meats 

 could not be attributed to bacterial action ; and no noticeable change 

 in the histological structure of the muscle fibers was noticed after 

 11 weeks of storage. 



The chemical changes which took place in the muscular tissues of 

 the beef during storage may be regarded as largely due to enzym 

 action. 



The principal effect of slorage upon the organoleptic properties 

 of the beef was a marked increase in tenderness of the meat. This 

 change did not appear to progress appreciably after the beef had 

 been held in storage for from two to four weeks. While the flavor 

 also changed, individuals would probably not agree as to whether 

 the change was in the nature of an improvement or a deterioration. 



Beef was lu'ld in cold storage at temperatures above freezing in 

 an experimental cooler for as long as 177 days, whereas it was pos- 

 sible to hold beef in storage in a cooler in a modern packing house 

 for ordy 55 days. The sliortcr stoi-age period in the second instance 

 was due to the much liiglier humidity of the packing-house cooler as 

 compared with the experimental cooler. 



The length of time that fresh beef can be held in cold storage at 

 temperatures above freezing and remain in wholesome condition is 

 dependent iipcm a niimV)er of factors, among which tlu^ temperature 

 and humidity of the storage room and tiie character of the beef are 

 of the most importance. 



