UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 740 



Contribution from the Bureau of Chemistry 

 CARL L. ALSBERG, Chief 



Washington, D. C. 



January 13, 1919 



A STUDY OF SOME OF THE CHEMICAL CHANGES WHICH 

 OCCUR IN OYSTERS DURING THEIR PREPARATION FOR 

 THE MARKET. 



By Edward E. Smith, Junior Chemist. 1 



CONTENTS. 



Page. 



Scope of investigation 1 



Commercial treatment of oysters 2 



Experimental work 3 



Methods of analysis 3 



Series 1 4 



Series II 6 



Page. 



Experimental work (continued): 



Series III 8 



Series IV 9 



Series V 13 



Summary 23 



SCOPE OF INVESTIGATION. 



This bulletin gives the results of an investigation to determine the 

 amounts of ammoniacal nitrogen, amino-acid nitrogen, moisture, 

 total solids, ash, and sodium chlorid present in oysters under the 

 various conditions through which they pass in ordinary commercial 

 practice in the oysterhouse, and to ascertain the effect of washing 

 and soaking on both the chemical composition and physical condition 

 of the oysters. The investigation was conducted during the fall and 

 winter of 1914-15, in certain oysterhouses in Connecticut, selected 

 as being representative of the oyster industry throughout the North 

 Atlantic States. The oysters used were grown in various beds, rang- 

 ing from New Haven, Conn., on the east, to Raritan Bay, N. J., on 

 the west. As work was done in several houses, each using a different 

 method of treatment of the stock, the methods given represent 

 commercial practice at that time and in that locality, but may not 

 be representative of later practice or other localities. The experi- 

 ments which were made to show the results of various special treat- 

 ments do not represent commercial practice. 



i The writer wishes to express his indebtedness to Dr. E. D. Clark and Mr. L. H. Almy, who instructed 

 him in the methods of determination of ammoniacal nitrogen and amino-acid nitrogen; to Mr. Carleton 

 Bates and Dr. Lester Round, who assisted materially in planning the work and under whose direction 

 it was carried out; and especially to Mr. R. W. Lamson, without whose help Series V would have been 

 impossible. 



' 77345°-19-Bull. 740— I 



