Simultaneous detection of eight species of tree nut in foods using two tetraplex polymerase chain reaction assays

Abstract

ABSTRACT Tree nuts comprise a category of food allergens that must be included in the food labels in several countries. We developed a polymerase chain reaction (PCR) method using eight specific primer pairs to detect eight representative tree nuts (almond, Brazil nut, cashew, hazelnut, macadamia nut, pecan, pistachio, and walnut) under the same experimental conditions. The specificity of the eight primer pairs was confirmed by PCR testing against a variety of plant and animal samples. The detection limit of the method ranged from 1 fg to 1 pg DNA of individual tree nuts. The method detected tree nut DNA in processed and unprocessed food. In addition, the primer pairs could be combined into two sets of tetraplex PCR system. The developed method is specific, sensitive, and efficient, making it useful for detecting trace amounts of eight species of tree nut in foods.