Development of a Competitive ELISA for the Detection of Pecan (Carya illinoinensis (Wangenh.) K. Koch) Traces in Food

Pecan nuts are included among the so-called big-eight food allergens, which are responsible for 90% of food allergies. However, unlike other tree nuts such as Brazil nut and hazelnut, studies on pecan from the point of view of allergies are scarce, and only a few analytical methods to detect its presence in food have been published. The objective of the present study was to develop an enzyme-linked immunosorbent assay (ELISA) method to detect traces of pecan in foods. Therefore, pecan-specific polyclonal antibodies were developed in rabbits and characterized for their specificity to pecan proteins and for their selectivity in challenging studies with other food ingredients and allergens. In addition, the research was complemented with more specific analyses like sodium dodecyl sulfate polyacrylamide gel electrophoresis to characterize the protein standard and western blot to identify the reactive proteins. By applying the selected conditions, the data were fitted to a four parameter logistic curve, which gave a R square of 0.999, and IC50 and IC80 values of 5.0 and 2.2 ng/mL, respectively. This highly sensitive method allows the detection of trace amounts of pecan protein within complex food matrices, which can provide the food industry with a useful tool to comply with the requirements enforced by regulatory agencies.