760 EXPERIMENT STATION RECORD. [Vol.36 



determine the length of time that fresh beef could be held in cold storage at 

 temperatures above freezing and remain in wholesome condition. Three dis- 

 tinctive lines of investigation were planned — autolysis experiments with fresh 

 beef, cold-storage experiments with fresh beef, and a study of the factors 

 affecting the length of time that beef could be held in cold storage. 



The results of the aseptic autolysis experiments showed the following : Physi- 

 cal changes were not marked and consisted chiefly of a slight softening of the 

 tissues, an exudation of juice, and a change in color of the meat. Total soluble 

 extract or total solids decreased early in the experiments and later increased, 

 while the ash of the extract showed appreciable although not regular increases, 

 which corresponded roughly with similar increases in the total soluble phos- 

 phorus. The acidity of the samples showed appreciable increases toward the 

 close of the experiment. The changes taking place in tlie nitrogenous com- 

 pounds consisted in general of an increase of total soluble nitrogen and a con- 

 version of the higher forms of soluble nitrogen compounds into simpler combina- 

 tions. Appreciable increases were noted in total soluble phosphorus and in 

 soluble inorganic pliosphorus, together with corresponding decreases in insoluble 

 and in soluble organic phosphorus. There was no development of free hydrogen 

 sulphid during the course of the experiment. 



The cold-storage experiments with fresh beef included bacteriological and his- 

 tological studies and also physical and chemical studies of the meat during 

 storage. The following conclusions are drawn from the bacteriological and 

 histological tests : 



"Certain bacteria (chiefly micrococci) may be normally present in the car- 

 casses of healthy animals slaughtered for beef. These bacteria possess no 

 pathological significance and do not appear to multiply in the cold-stored car- 

 casses, provided the cold-storage room is maintained at the proper temperature. 

 Bacteria and molds grow on the surface of cold-storage carcasses but do not 

 penetrate to any great depth (less than 1 in. in 177 days) ; bacteria apparently 

 are not concerned in the changes leading to increased tenderness in cold-stored 

 meats. Microscopic sections failed to show any noticeable histological changes 

 in the muscular tissue after 77 days of storage." 



" 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 solulMe inorganic phosphorus ; while decreases 

 occurred in coagulable nitrogen and in soluble organic pliosphorus. 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." 



These changes were similar in nature to, but less in extent than, those caused 

 by enzymatic action when lean beef underwent aseptic autolysis 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 tlie nutritive value 

 or the wholesomeness of the edible portions of the product ; but the changes 

 that took place in the kidney fat and external fatty tissue after the longer 

 periods of storage rendered them unsuitable for human consumption. . . . 



" 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 



