CHANGES IN" FRESH BEEF DURING COLD STORAGE. 95 
explained by the comparatively large increases in the amount - of free 
fatty acids present in those samples. 
Free fatty acids.- — There was a marked and continuous increase in 
the free fatty acid content of the external and kidney fats during 
the course of the storage experiments and a corresponding deteriora- 
tion in the quality of those fats. The average actual increase in the 
acidity of the two fats ranged from 0.46 per cent in the case of the 
beef stored 14 days to 9.76 per cent in the case of that stored 177 days. 
The changes in the acidity of the intermuscular fat were compara- 
tively small, varying from an increase of 0.17 per cent in the case of 
the beef stored for 14 days to an increase of 1.42 per cent in the 
case of that stored for 74 days. The reason for the slight increase in 
the acidity of the intermuscular fat as compared with the large 
increases in the acidity of the kidney and external fats is clearly ap- 
parent. The intermuscular fat was protected from bacteriological 
invasion by its covering of muscular and external fatty tissues, while 
the kidney and external fats were exposed to the invasion of molds 
and bacteria. The changes that took place in the intermuscular fat 
were due, in very large part at least, to the action of the enzym 
lipase, while the changes that took place in the kidney and external 
fats were due principally to bacterial action. 
EFFECTS OF COLD STORAGE UPON THE NUTRITIVE VALUE OF 
THE BEEF. 
Several factors must be taken into consideration in order properly 
to interpret the results of these experiments in terms of their effect 
upon the nutritive value of the meat. The more important factors 
are as follows: (1) Changes in the moisture content of the meat; 
(2) changes in the proportions of nonedible and edible meat in the 
quarters of beef; (3) changes in the composition of the meat. 
The analytical data obtained in these experiments show that, with 
the exception of the quarter of beef that had been stored for 14 days, 
each of the quarters lost moisture during storage, and that in general 
the decrease in the moisture content of the meat was greater the 
longer the storage period. This loss of moisture is in effect a process 
of concentration, causing an actual increase in the amount of food 
constituents present in a given weight of stored meat, as compared 
with that present in a like weight of fresh meat. Thus, by referring 
to Tables 19, 26, 33, 40, 47, and 54 it may be noted that the average 
percentages of total nitrogen, fat, and ash increased during the 
storage period of each experiment, and that in general the increase 
was greater the longer the period of storage. These data show the 
composition of the lean meat and are a. fair indication of the extent 
to which the nutritive value per given weight of meat was increased 
through loss of moisture. 
The increase in nutritive value, however, is only apparent, not 
real ; for while the loss of moisture effects an increase in the nutritive 
value of the meat per unit weight, it also diminishes the weight of 
the carcass; so that at best the carcass contains no more nutritive 
material after storage than before. Indeed, the available food ma- 
terial in the carcass tends to become less ; for, in consequence of the 
drying out and deterioration in quality of the exposed muscular and 
fatty tissues, there is greater wastage in the preparation of the retail 
