Multiplexed Detection of Mycotoxins in Foodstuffs using Protein Arrays

Considerable effort is currently directed toward generating fast and robust devices for the detection of various food pathogens. Traditional methods for the detection of toxins employ high pressure liquid chromatography and mass spectrometry, preceded by significant steps of sample preparation to eliminate interference from other components like sample matrix. Within the last years arrays of both proteins and nucleic acids proved to be a powerful tool in genomic and proteomic research and are now increasingly finding use in the area of food safety. Especially immunologically-based assays are growing in popularity and acceptance because of their reduced requirement of extensive sample preparation.
We have developed an antibody-based microarray technique for the multiplexed detection of mycotoxins in foodstuffs or animal feed. Mycotoxins such as zearalenone, orchatoxin A, deoxynivalenol and aflatoxin B1 are catabolic products of mould resulting in toxic effects on humans and animals. Our quantitative detection method is based on a multiplexed competitive immunoassay: toxin-specific monoclonal antibodies are immobilized on epoxy-coated slides, mycotoxin standards (labelled with different fluorophores) and unlabelled toxins in the sample of interest compete for binding sites of spotted antibodies and thereby enable a correct quantification. Cross-reactivity between toxins and antibodies was examined as well as the shelf-life of spotted arrays. Sample preparation steps could be reduced to a minimum and the different sample matrices tested showed no significant influence. In general, the presented antibody microarray enables the rapid detection of mycotoxins in a sub-ppm range with excellent recovery rates.