BUEEAU OF ANIMAL. INDUSTKY. 267 



The laboratories have examined a large number of coloring mate- 

 rials offered for use in coloring sausage casings and rendered fats. 

 The great majority of coloring materials offered in this way have 

 been rejected on account of the presence of arsenic, it having been 

 decided that no coloring matter should be used on meat food products 

 ■which contained more arsenic than 1 part in 700,000 of the coloring 

 substance. 



A number of inspections have been made of meat food products in 

 order to determine their wholesomeness. This examination applied 

 mainly to the rancidity of fats and oils and to the wholesomencss of 

 certain supected samples of canned meats. Inspectors have been in- 

 structed that in all cases " blown " or " puffed " cans of meat food 

 products should be condemned, the puffing of the cans being due in all 

 cases to the de^'elopment of bacteria within the can after the process 

 of canning was completed. 



During the fiscal j^ear 115 sanitary examinations of packing-house 

 water supplies have been made. The results of these examinations 

 have been to prohibit the use in or on meats or meat food products of 

 15 water supplies which were found to be of questionable whole- 

 somencss. 



RESEARCH AVORK ON MEAT PRODUCTS. 



The research work in connection with the laboratory meat inspec- 

 tion has consisted in part of the study of existing methods of analy- 

 sis, in order that these might be improved where possible and that the 

 effect of interfering factors might be more thoroughly understood. 

 In addition, a number of questions arising in connection with the 

 enforcement of the meat-inspection law have been given special study. 



A general study has been made of the rancidity of fats and the 

 changes which accompany the development of this condition. The 

 general work is far from completed, but opportunity has been afforded 

 for a study of the effect of rancidity on various routine tests which 

 are applied to fats in the course of a laboratory inspection. The 

 Kreis test for rancidity has been studied considerably, and it has been 

 found that it is a reliable indicator of rancidity, but so exceedingly 

 delicate that a certain amount of caution and judgment must be used 

 in drawing conclusions from it. The Halphen test for cotton-seed oil 

 has been found to be weakened and the iodin number of fats reduced 

 by the development of rancidity, thus confirming previous observa- 

 tions. The effect of rancidity on the percentage of free fattv acids 

 appears to be in the nature of a reduction at first, and later, after the 

 fat has become strongly rancid, the proportion of free fatty acid in- 

 creases. The phytosterol test is rendered unreliable by the develop- 

 ment of rancidity. 



Soy-bean oil is now being used in the preparation of meat food 

 products, especially oleomargarin. A study of the pure oil has been 

 undertaken, but is not yet completed. Enough has been accom- 

 plished, however, to enable the laboratories to deal with any attempt 

 to use this oil as an adulterant. Considerable study has also been 

 given to the coloring matter contained in the soy-bean oil. The col- 

 oring matter has been separated from the oil and a study made of its 

 chemical properties. 



