10 BULLETIN 433, U. S. DEPAETMENT OF AGRICULTURE. 



sis and placed in cold storage until the next day, when it was pre- 

 pared for chemical examination. Analytical work was started prac- 

 tically 24 hours after slaughter, during which time the material used 

 for analysis had been in cold storage 17 hours. All work in the 

 preparation of the material for analysis, including the weighing of 

 the material for individual determinations, was carried on in a refrig- 

 erated room at a temperature between 32° and 40° F. After the 

 fresh material had been ground as finely as possible and transferred 

 to glass jars which were then tightly stoppered, chemical work was 

 started forthwith. In the case of the incubated samples, as soon as 

 cultures had been taken for bacteriological examination, the dishes 

 were again sealed and placed in a refrigerated room at a temperature 

 of 24° F. for 2 or 3 days or until results had been obtained from 

 the bacteriological examination of the samples. The meat was then 

 prepared for analysis by the same methods used with the fresh 

 material. 



PHYSICAL AND ORGANOLEPTIC CHANGES, 



The sterile samples showed increasing losses in weight as the ex- 

 periment progressed, ranging from 0.8 per cent in the sample in- 

 cubated 7 days to 10.08 per cent in the sample incubated 100 days. 



Certain observations on changes in the character of the samples 

 during incubation may be of interest. The sample which had been 

 incubated 7 days showed the following characteristics : There was no 

 apparent disintegration of the tissues and the piece of meat had 

 retained practically its original form ; considerable juice had exuded 

 which had turned light brown in color and which contained consid- 

 erable sediment of a grayish-white color; after the dish had been 

 opened and cultures for bacteriological examination had been taken, 

 a strip of moist lead paper was inserted as a test for hydrogen sul- 

 phid, but no reaction was obtained ; the exposed surface of the meat 

 was light brown in color, while the surface which rested on the bot- 

 tom of the dish was bright-pink in color. The cutting of a cross 

 section showed that the meat was somewhat rubbery in texture and 

 not noticeably tender. The cross section showed a brown zone ex- 

 tending inward for a distance of about one-fourth of an inch from 

 the surface, except where the meat had rested upon the bottom of 

 the dish, where the pink color extended to the surface. The interior 

 of the sample was of a uniformly bright-pink color. The meat had a 

 pleasant odor, somewhat similar to that of rare roast beef. The re- 

 mainder of the sterile samples, which had been incubated for periods 

 ranging from 14 to 100 days, showed characteristics so similar to 

 those of the sample just described that a separate description of each 

 sample does not seem to be necessary. 



