Use of Radioimmunoassay to Determine the Nature, Quantity and Source of Allergenic Contamination of Sunflower Butter

A girl known to be allergic to peanuts experienced a mild allergic reaction after eating sunflower butter, a peanut butter facsimile prepared from sunflower nuts. After learning that the same manufacturing plant also produced peanut butter, we examined several sunflower butter preparations for peanut butter contamination by a solid-phase radioimmunoassay which used naturally-occurring immunoglobulin E (IgE) antibodies from known peanut-sensitive individuals. Peanut butter contamination, ranging from 0.3 to 3.3%, was found in six of eight sunflower butter samples, including both creamy and chunky varieties, and including lots prepared with either peanut oil or palm oil. We concluded that inadequate cleaning of food processing machines following peanut butter production permitted the contamination by peanut butter of subsequent jars of sunflower butter in amounts which could pose risks to peanut-sensitive individuals.