The major allergen in apples, Mal d 1, is a "pathogenesis-related (PR) protein." These allergens are secondary metabolites produced by plants in response to one or more sources of stress.

Researchers found that organically grown apples had two- to six-times lower levels of Mal d 1 allergen in three out of four tests encompassing two varieties at each of two locations. The team speculated that the pesticides applied to the conventionally grown apples were, to some degree, phytotoxic to the trees, imposing stress and triggering the production of the Mal d 1 allergen in response.

Anne Matthes and Michaela Schmitz-Eiberger, "Apple (Malus domestica L. Borkh.) Allergen Mal d 1: Effect of Cultivar, Cultivation System, and Storage Conditions," Journal of Agricultural and Food Chemistry, Vol. 57, No. 22, November 25, 2009

Courtesy of Garden Organic

First published in November 2009

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