Mycotoxin Testing Paradigm: Challenges and Opportunities for the Future

Mycotoxins are one of the great global challenges to agri-food and feed safety. Industry requires fast, reliable, and economical testing methods for the most important regulated mycotoxins to manage this problem. Climate change and changes in agricultural practice are complicating this situation, triggering the movement of some mycotoxins into new regions, which are unprepared for their management. Modern LC-tandem MS (LC-MS/MS) instruments have addressed this analytical challenge, but such instruments are expensive and require highly qualified personnel and dedicated facilities. As a result of these limitations, traditional LC-MS/MS is not amenable for use on farms or at small to midsized processing facilities, such as a grain elevator. To address the need for on-site rapid testing, the mycotoxin community has focused on antibody-based and spectrophotometric approaches. The development of innovative technologies such as miniaturized MS would allow for the acquisition of more information on mixtures of toxins present in a sample at costs comparable to those of the existing rapid methods such as ELISA. The capital costs are higher, but it would reduce per-sample testing costs and time requirements and provide better value for money while maintaining the accuracy and selectivity achieved in a laboratory setting. In this article, we review the available techniques and contrast them in the context of three main criteria: method performance, speed of analysis, and cost. We define the integration of these three parameters as the "mycotoxin testing paradigm.

Natural Product Discovery with LC-MS/MS Diagnostic Fragmentation Filtering: Application for Microcystin Analysis

Natural products are often biosynthesized as mixtures of structurally similar compounds, rather than a single compound. Due to their common structural features, many compounds within the same class undergo similar MS/MS fragmentation and have several identical product ions and/or neutral losses. The purpose of diagnostic fragmentation filtering (DFF) is to efficiently detect all compounds of a given class in a complex extract by screening non-targeted LC-MS/MS datasets for MS/MS spectra that contain class specific product ions and/or neutral losses. This method is based on a DFF module implemented within the open-source MZmine platform that requires sample extracts be analyzed by data-dependent acquisition on a high-resolution mass spectrometer such as quadrupole Orbitrap or quadrupole time-of-flight mass analyzers. The main limitation of this approach is the analyst must first define which product ions and/or neutral losses are specific for the targeted class of natural products. DFF allows for the subsequent discovery of all related natural products within a complex sample, including new compounds. In this work, we demonstrate the effectiveness of DFF by screening extracts of Microcystis aeruginosa, a prominent harmful algal bloom causing cyanobacteria, for the production of microcystins

Aflatoxin exposure in Nigerian children with severe acute malnutrition

Aflatoxin exposure is an important public health concern in sub-Saharan Africa as well as parts of Latin America and Asia. In addition to hepatocellular carcinoma, chronic aflatoxin exposure is believed to play a role in childhood growth impairment. The most reliable biomarker of chronic aflatoxin exposure is the aflatoxin-albumin adduct, as measured by ELISA or isotope dilution mass spectrometry (IDMS). In this report, we have used high resolution LC-MS/MS with IDMS to quantitate AFB1-lysine in an extremely vulnerable population of Nigerian children suffering from severe acute malnutrition. To increase the sensitivity and reliability of the analyses, a labelled AFB1-13C6 15N2-lysine internal standard was synthesized. AFB1-lysine concentrations in this population ranged between 0.2 and 59.2 pg/mg albumin, with a median value of 2.6 pg/mg albumin. AFB1-lysine concentrations were significantly higher in stunted children (median = 4.6 pg/mg) compared to non-stunted (1.2 pg/mg), as well as in children with severe acute malnutrition (4.3 pg/mg) compared to controls (0.8 pg/mg). The median concentrations were also higher in children with kwashiorkor (6.3 pg/mg) compared to those suffering from marasmus (0.9 pg/mg). This is the first report of the use of high-resolution mass spectrometry to quantitate AFB1-lysine in humans