Parthenolide in Danish biodynamic and organic milk: A new source of exposure to an allergenic sesquiterpene lactone.

This is the first report of a potent contact allergen in milk. There seems to be an association between the time that the dairy cattle spend grazing and the amount of parthenolide detected. Although the concentration is low, it is estimated to be high enough to elicit dermatitis in the most sensitive persons by direct contact with the milk.