Anaphylaxis in a milk-allergic child after ingestion of milk-contaminated kosher-pareve-labeled "dairy-free" dessert.

Milk-allergic persons often rely on kosher labeling to select dairy-free foods. A 2-year-old boy experienced multiple generalized reactions after ingestion of milk or milk products; his serum contained elevated levels of milk-specific IgE antibodies, and his milk skin test was strongly positive. An identical reaction occurred after ingestion of "pareve"-labeled raspberry sorbet. Using an inhibition immunoassay with pooled sera from two milk-sensitive persons as the source of IgE antibodies, we found the milk allergen level in sorbet provided by the family to be 11% of the level found in non-fat dry milk. The milk allergen level in three independently purchased containers of sorbet ranged from 2% to undetectable. The presence of milk in three of four of the sorbets was confirmed by immunoblotting studies, by quantitation of milk proteins by polyacrylamide gel electrophoresis, and by quantitation of lactose by gas chromatography. Subsequently, it was discovered that milk was incorporated into the sorbet when equipment used to package ice cream had been used to package the sorbet. Although kosher labeling may provide assurance to milk-sensitive persons that a particular food does or does not contain milk, such labeling is no guarantee that this is indeed the case.