DETECTION AND IDENTIFICATION OF FORMALDEHYDE IN GADOID FISH
1963 Volume 29 Issue 7 Pages 695-701
Details
1963 Volume 29 Issue 7 Pages 695-701
The purpose of this work indicated in the title was motivated by the request of the Sanitary Inspection Office of Tokyo Fish Market and related agencies. Because sanitary check conducted at the market in December 1961 was led a suspicion that formaldehyde or its causative agents might have been used for an amount of cod, Gadus macrocephalus landed in frozen state from some parts of the Northern North Pacific.
In the experiments the authors carried out to clarify the point, a major portion of materials used consisted of the cod and Alaska pollock, Theragra chalcogramma which were either caught at the sea in question or caught in coastal waters off Japan. The conclusion from the experiments is that these species of fish almost always contain an amount of formaldehyde by nature. This is based on the following evidences.
1) Before confirming the presence of formaldehyde, preliminary tests were performed by both Rimini's reaction and a method modified by Yanagisawa and Maruyama from Hehner's. The test solution was prepared by distilling filtrate of fish meat which was made free from protein and other disturbing substances by adding sulphuric acid and phosphotungstic acid to meat samples each from different species of fish.
Among various fishes examined, the cod and the Alaska pollock positively reacted to the both tests (Table 1), with the reaction observed in the sample solutions not only of the muscle but also of other tissues of these species (Table 2).
2) In the subsequent experiments to identify the substance reacting to the tests, phosphotungstic acid was added to the cod meat to eliminate protein and then it was filtered. In the presence of dimedone added to the filtrate, needle crystals of formaldimedone were obtained (Table 3).
3) Quantitative determination of formaldehyde was carried out by Nash's method for various tissues and parts of the cod and Alaska pollock, such as skin, muscle, liver, pyloric caeca, gonads, intestine, stomach and stomach contents. A maximal level of the formaldehyde contained in the muscle was 15mg% (Tables 4 and 5).
