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, noncoagulable, 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 storage 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 held 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 only 55 days. The shorter storage period in the second instance 
was due to the much higher 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 upon a number of factors, among which the temperature 
and humidity of the storage room and the character of the beef are 
of the most importance. 
