BUREAU or CHEMISTRY. 221 



SEA FOODS. 



Bulletin 740, "A Study of Some of the Cliemical Changes Which 

 Occur in Oysters During Their Preparation for the Market," has 

 been issued. It has been discovered that zinc, like copper, is invari- 

 ably present in oysters, and probably in other molhisca. No rela- 

 tion could be traced between the zinc content of oj'sters and that 

 of the waters from "which they were taken. The data upon which 

 these conclusions are based have been published. At the request 

 of the Bureau of Fisheries a study was made of trade-waste effluents 

 at Bridgeport, Conn., and "West Point, Va., to determine the influence 

 of such effluents upon the production of oysters in these localities. 



Analyses have been made at various seasons of Pacific coast fishes, 

 the food value of which is not known, and the results will be pub- 

 lished when another season's work has been completed. Informa- 

 tion on the preservation of Pacific coast sardines by smoking has 

 been disseminated, and a publication on the preparation of salacchini 

 will soon appear. The project to develop methods for the preserva- 

 tion of Pacific coast fish will be discontinued because funds are no 

 longer available. 



Bacteriological ex;\mination has shown that, as reported last year 

 for Maine sardines, and published this year, the intestines of salmon 

 and certain other fish that are not feeding are practically sterile. 

 Evidently in the spoilage of such fish the bacterial invasion is from 

 the skin inward, not from within the gut outward. Hence knowl- 

 edge of the resistance offered bv the skin of various kinds of fish 

 to invasion by bacteria is of importance in determmnig the best 

 methods of handling eacli species. Preliminary data indicate that 

 the skin of different species varies appreciably in this respect. It 

 follows, moreover, that in handling and transporting manj^ kinds of 

 fish it is of the utmost importance to avoid any injury or bruising 

 of the skin. 



The changes that take place in the flora of fish during shipment 

 to market or canner}^ and during cold storage have also been studied, 

 especially the microorganisms found on Pacific salmon. A related 

 inquiry upon an aerobic spore-forming bacillus from canned salmon 

 has been prepared for publication. In addition, search has been made 

 for satisfactory chemical methods to detect spoilage of salmon, and to 

 karn the conditions under which the fish may become stale in the 

 cannery before being packed. While satisfactory ])rogress has been 

 made, at least another year will be required for the compeltion of 

 tiie project. 



A paper on the determination of the hexabromid and iodin values 

 of the oil of salmon as a means of identifying the species in the 

 canned product has been published. 



Progress has been made in the study of the best methods of trans- 

 porting fresh fish. Some shippers have been induced to substitute 

 for barrels used as shipping containers 100-pound boxes, 30 inches 

 long by 15 inches wide by 15 inches deep. In such boxes the lower 

 layers of fish are not subjected to as much pressure and bruising as 

 in barrels or when shipped loose with ice in the bottom of refrigera- 

 tor cars. Study has shown that in barrels the pressure upon the 

 lower layer of fish may be so great as to produce a shrinkage of over 



