126 ANNUAL REPORTS OF DEPARTMENT OP AGRICULTURE. 



a marked increase in acidity, accompanied by a certain degree of 

 rancidity, sufficient, in some cases, to render the fat unsuitable for 

 food. The principal effect of storage upon the organoleptic proper- 

 ties of beef consisted in a marked increase in the tenderness of the 

 meat. This change took place in from 14 to 28 days, but did not 

 appear to progress appreciably during continued storage. The 

 bacteria and molds which grew on the surfaces of the meat in storage 

 did not penetrate the muscular tissue to any great depth, and no 

 change in the histological structure of the muscle fiber was notice- 

 able after 177 days of storage. It appears that the increased ten- 

 derness of the meat in storage can not be attributed to bacterial 

 action, but probably results from the action of enzyms normally 

 present in the muscular tissue. 



Although it was found to be possible to hold meat for 177 days in 

 a small cold-storage room used for experimental purposes, similar 

 pieces of meat could not be held in storage at the same temperature 

 in the cooler of a modern packing house for longer than 55 days. 

 The difference in the keeping quality of the meat m the two coolers 

 is to be attributed to the much greater humidity of the packing- 

 house cooler. The length of time that fresh beef can be preserved in 

 a wholesome condition in cold storage at temperatures above freezing 

 is dependent upon a number of factors, chief among which are the 

 temperature and humidity of the storage room and the condition of 

 the beef when placed in storage. A paper describing these experi- 

 ments, prepared by Kalph Hoagland, C. N. McBryde, and W. C. 

 Powick, has been submitted for publication. 



In connection with the cold-storage experiments, certain portions 

 of sterile muscular tissue of beef were held under aseptic conditions 

 at 98.6° F. for various periods of time. It was found that under 

 these conditions there was a marked transformation of the muscle 

 creatin into creatinin. This change is ascribed to the action of 

 enzyms occurring normally in the muscular tissue, and the findings 

 throw interesting light upon a certain phase of tissue metabolism. 

 The results of this work have been published in the Journal of Agri- 

 cultural Research. 1 



In subsidiary investigations carried along during the regular 

 cold-storage studies it was found that when ox muscle, obtained 

 under aseptic conditions, is incubated at 98.6° F. for various periods 

 of time, the natural coloring matter of the meat, oxyhemoglobin, is 

 transformed into hematoporphyrin. These observations are of much 

 importance because of their possible significance concerning the for- 

 mation of bile pigments in the body. It appears not improbable 

 that hematoporphyrin is an intermediate product in the form of 

 bile pigments, the hematoporphyrin being formed in the muscular 

 tissue and later changed into bile pigments by the liver. A report 

 of this work has been published in the Journal of Agricultural 



Research. 2 



Besides the above-described research work, there has been de- 

 veloped during the year a satisfactory method for the determination 

 of sugar in meats. A detailed report of this work will be submitted 



* " Effect of autolysis upon muscle creatin." By Ralph Hoagland and C. N. McBryde. 

 Journal of Agricultural Research, vol. 6, p. 535. . u„i„i, n~o„ 



a " Formation of hematoporphyrin in ox muscle during autolysis. By Kalph Hoag- 

 land, Journal of Agricultural Research, vol. 7, p. 41. 



