Soyez prudent(e)s: Toxicité des crosses de fougère

Les crosses de fougère (la partie non-déroulée ou la feuille de cette fougère comestible) font vraiment partie de notre patrimoine naturel et culinaire. Elles représentent une composante habituelle du régime alimentaire des Néo-
Brunswickois(es) depuis au moins la fin des années 1700 et les fougères ont été un légume printanier important pour les autochtones de l’Est de l’Amérique du Nord depuis bien plus longtemps encore.

L’auteur Jim Goltz nous explique que les rapports concernant les toxi-infections alimentaires causées par les crosses de fougère ont mené à la recommandation que cet aliment soit complètement cuit avant la consommation.

Une "cuisson complète" signifie bouillir, ou cuire à la vapeur, pendant au moins 10 minutes. Prévenir la maladie pour votre famille et vos ami(e)s est plus important que la perte nutritive un peu plus élevée et la texture un peu moins ferme qui résulte d’une cuisson plus longue.

Jim fait remarquer qu’il nous faut être prudent(e)s de ne pas cueillir trop de crosses de fougère d’une même plante afin de s’assurer que cette ressource naturelle excellente puisse continuer à se régénérer.

The fiddlehead
is a delicious and nutritious sign of spring and a New Brunswick tradition
worth preserving

Be Aware: 
Fiddlehead (Ostrich Fern) Toxicity

James Goltz
NB Protected Natural Areas Coalition
Previously published in the N.B. Naturalist
Volume 22, Issue 1, March 1995

he fiddlehead, crosier, or tête-de-violon, enjoyed by so many persons in the Maritime Provinces and the northeastern United States, is actually the unfurled frond or leaf of the Ostrich Fern.

(photo: NB Image Bank)

Fiddleheads are truly a part of our natural and culinary heritage, having been a regular component of the diet of New Brunswickers since at least the late 1700s and an important spring vegetable for aboriginal people in eastern North America for considerably longer. In recent years, other geographic areas have begun to share our appreciation for this delicious spring "green", and the consumer market continues to expand.

Most reference books indicate that fiddleheads are safe to eat either raw or cooked. However, several outbreaks of food poisoning associated with eating raw or lightly cooked (sautéed, par-boiled or microwaved) fiddleheads occurred in western Canada and New York State in 1994. The affected persons experienced diarrhea, nausea, abdominal cramps, vomiting and/or headache, usually within a few hours after consuming fiddleheads. In most of the 64 persons who were affected, the symptoms had abated within 30 hours after their onset. The majority of individuals who became ill had eaten fiddleheads in restaurants, but a few had purchased them at local markets and prepared them at home. Since the publication of these outbreaks, other anecdotal retrospective reports of fiddlehead food poisoning have surfaced. (With some embarrassment, I must report that one of my dinner guests once became sick shortly after eating stir-fried fiddleheads. Two other guests were not affected.)

Although the specific cause of illness in these disease outbreaks could not be determined, epidemiological studies determined fiddleheads to be the source of the problem. Given the short incubation period between eating fiddleheads and becoming sick, it was hypothesized that the fiddleheads must have contained an unidentified toxic substance. In all cases, the fiddleheads had been collected from sites located some distance from any development or industry, there had been no pesticide spraying in the areas, and storage and handling could not be faulted. Laboratory testing failed to reveal any significant bacteria, bacterial toxins, pesticides or other chemicals that might have caused the illness. It is interesting to note that rats and mice remained healthy after being fed raw and cooked fiddleheads from the same sources.

(photo: NB Image Bank)

The reports of fiddlehead food poisoning have lead to the recommendation that fiddleheads be thoroughly cooked before eating. Medical experts suggest that "thorough cooking" means boiling or steaming for at least 10 minutes. Preventing illness among your family members and friends is worth the slight increase in nutrient loss and the soggier texture that occurs with longer cooking times. Incidentally, the unfortunate dinner guest to whom I made reference above, has since found that he can eat well-cooked fiddleheads with abandon, but consistently becomes ill if the fiddleheads have not been well-cooked! My fiddlehead ice cream, fiddlehead quiche, and curried fiddlehead soup have caused her no digestive upset.

Since the ingestion of some fern species, e.g. bracken fern, has been linked with certain types of cancer, persons who gather fiddleheads should be certain that they are harvesting the correct species. Inexperienced "fiddleheaders" should accompany seasoned veterans.

On a final note, we must take care that, in our zealous harvesting adventures, we refrain from taking more that a few fiddleheads from each plant so that our bountiful natural resource will be sustainable. The fiddlehead is a delicious and nutritious sign of spring and a New Brunswick tradition worth preserving (in both senses of the word!)

Reference: Morgan, P., et al 1994. Ostrich Fern Poisoning - Western Canada and New York, 1994. Canada Communicable Disease Report 20 (18): 160-162.