Title: “Masked” mycotoxin detection: What is a poor chemist to do? Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 8, 2013
Publication Date: N/A
Technical Abstract: Novel fungal toxins and metabolites of known toxins that have not been amenable to easy detection using established reference methods are routinely termed “masked” mycotoxins in the literature. Typically these are metabolites that are structurally related to mycotoxins of economic importance, but which are not observed directly during screening of commodities or foods. Examples are glucosides that have been observed for many mycotoxins. Aside from concern about the toxicity of the compounds themselves, there is concern about the possibility that they may serve as reservoirs for the parent toxin. With the recent widespread application of liquid chromatography-mass spectrometry, in particular the application of highly selective mass detectors, detection of masked mycotoxins has become more feasible. This presents a new set of issues for analysts, not the least of which is nomenclature (is a masked mycotoxin really ‘masked’ if you can detect it?). Functionally the issues are more significant: given limited resources, which of these congeners are worth detecting and quantifying? Also, cost is a real issue, and the ideal detection system will detect the desired analytes in a cost effective manner that supports monitoring, rather than impedes it. For good reason analysts generally have greater confidence in methods that directly detect toxins, based on physical or chemical properties, rather than those that indirectly detect toxins, such as immunoassays. However, field applications of direct detection techniques still face significant obstacles. Conversely, field applications of immunoassays are well established. Such assays can be inexpensive to produce and require minimal training for operation, which are significant advantages for screening methods. One of the major issues for detecting masked mycotoxins by immunoassay is whether the antibodies directed against the parent toxins, which are the basis for screening kits, are able to bind with, and detect, the metabolites of interest. Trichothecene mycotoxins, such as T-2 toxin, are common contaminants of commodities and foodstuffs. Recently the glucosides of T-2 toxin were discovered and their presence was detected in commodities. In order to improve the isolation and detection of T-2 glucosides, several antibodies directed against these masked mycotoxins were developed and applied in a biosensor for detecting them in wheat. The strong cross-reactivity of several of these antibodies with both T-2 toxin and its glucoside suggests that detection of the two analytes together, as a combined response, may be feasible. This is a first step in addressing the issue of the simultaneous detection of masked mycotoxins, along with their parent toxins, in foodstuffs using rapid screening assays.