"Not more than one can should be taken from any one case in sampling. 



February 28, 1941." 



In actual practice viiile a state supervisor or inspector may be in 

 a cannery or about the wharfs or promises, he seldom personally makes 

 routine inspection either of the raw fish during butchering or of the 

 precooked fish„ This work is gaierally carried out ty one of the 

 cannery personnel for most lots of fish passing through the cannery. 

 Only in cases of suspected spoilage would, as a rule, the state in- 

 spector take an active part. 



Those tuna vdiich are iced, rather than frozen, sometimes are held 

 long enough for spoilage to develop. Fish frozen aboard clipper ships 

 usually are frozoi within such a short period of time that no spoilage 

 can take place. However, in a few instances fish have been allowed to 

 stand on deck in the hot sun for an excessive period of time (in hot 

 equatorial regions this may be only a few hours) and such fish are then 

 partially spoiled before freezing is complete. Spoilage is usually 

 detected during butchering; on rare occasions it may not show up until 

 after pre cooking either: in the foim of an off -odor or as honeycombing. 



When a state inspector detects spoilage in a lot of fish he advises 

 the cannery to stop packing that lot of fish. In a borderline case the 

 packer may feel that the condition of the fish does not warrant such 

 action and he may continue to pack it. In such a case, samples of the 

 raw fish, or more frequently, of the canned product are shipped to the 

 Fish Laboratory at the Hooper Foundation vdiere both organoleptic and 

 chemical examination of the fish are made. The chemical examination 

 for tuna spoilage consists of the test developed by Dr. Farber of the 

 Hooper Foundation for volatile reducing substances. The test involves 

 the collection of any volatile substances which can be swept away fron 

 neutral fish press juices by aeriation. The gases so collected are 

 passed through an alkaline potassium permanganate solution and the 

 excess permanganate determined by titration. Results are expressed 

 as microequivalents per 5 nil. of press juice. For canned tuna, products 

 having less than 15 microequivalents of volatile redicing substainces 

 per 5 ml, of press juice are considered acceptable vhile values in ex- 

 cess of 20 show definite decomposition. Values between 15 and 20 are 

 borderline, indicating fish of questionable acceptability. If the 

 laboratory reports that a lot of fish is not acceptable the State 

 Public Health Department issues an order preventing the fish from being 

 canned J, or if already canned, prevaiting the particular coded lot of 

 canned fish 'from being marketed. Such fish are usually reduced to 

 fish meal for animal feed. 



331 



