Ber e 1, a major allergen from Brazil nuts, is very stable to in vitro peptic digestion. As heat-induced denaturation may affect protein digestibility, the denaturation behaviour of Ber e 1 was investigated. The denaturation temperature of Ber e 1 varies from approximately 80¿110 °C, depending on the pH. Upon heating above its denaturation temperature at pH 7.0, the protein partly forms insoluble aggregates and partly dissociates into its polypeptides, whereas heating at pH 5.0 does neither induce aggregation, nor dissociation of the protein. The denaturation temperature of approximately 110 °C at pH values corresponding to the general pH values of foods (pH 5¿7) is very high and is expected to be even higher in Brazil nuts themselves. As a result, it is unlikely that heat processing causes the denaturation of all Ber e 1 present in food products. Consequently, the allergen is assumed to be consumed (mainly) in its native form, having a high stability towards pepsin digestion