Eating certain types of butterfish (e.g. in sushi dishes) may cause serious digestive problems in sensitive individuals!
The term “butterfish” comprises various, partly not even related types of fish. While true butterfish belong to the perch order and are considered excellent food fish, snake mackerels (e.g. escolars), which are also often labelled butterfish, may cause health problems in sensitive individuals.
Regulation (EC) No. 853/2004 regulates in its Annex, Section VIII, Chapter VIII under litera E: “fresh, prepared, frozen or processed fishery products of the Gempylidae family, in particular Ruvettus pretiosus and Lepidocybium flavobrunneum, may only be placed on the market in wrapped or pre-packed form and labelled with adequate amounts of consumer information regarding preparation/cooking methods and information on the risks of substances potentially contained in the product that could cause gastrointestinal disorders.”
This kind of information is often difficult to find for consumers. The appropriate information is usually missing from retail counters and restaurants. A preparation method for snake mackerel that is appropriate for the prevention of gastrointestinal disorders has not been identified to date. Conventional preparation methods (frying, smoking, as sushi, etc.) do not guarantee the removal of the wax ester which is responsible for causing health problems. Furthermore, it is not clear how much must be ingested to cause any such health problems.