Possible Toxic Components in Smoked Fish Products

Abstract

There is reason to believe that the ordinary processes involved in the smoking of fish and other foods could give rise to substances associated with risk of health. The two main sources of such substances are: (a) Deposition of the food of smoke constituents (b) Reaction between smoke and food constituents In the case of (a), toxic substances can arise from the destructive distillation of wood and from the vaporisation or decomposition of wood preservatives. The main focus of concern is polynucleararomatic hydrocarbons (PNAH) that are known to be present in wood smoke and whose concentration in foods is known to increase during smoking. Phenols, which are main constituents of wood smoke but probably of secondary concern, are known to promote the activity of carcinogens. With untreated wood destructive distillation is the only source of hazard and, of course, only untreated wood should be used for smoking. Unfortunately, it is becoming increasingly difficult to obtain supplies of untreated wood. Most soft woods used in the UK for example are treated with fungicides and insecticides such as chlorophenols (CP) and arsenicals. It is suspected that some treated wood is being used accidentally for smoking food. The principal risk arises from the volatilisation of CP but there is also the possibility that chlorinated dibenzo-p-dioxins (CDD) either present in the original commercial preparations of CP or formed subsequent to treatment (Fig. 1) could also be deposited. Certain isomers of CDD are known to be very highly toxic.