Using LC-MS/MS to Monitor Mycotoxin Contamination in Malting Barley

One of the major food safety issues for cereal crops is mycotoxin contamination from Fusarium mold species. Under certain environmental conditions, this filamentous fungus can colonize growing cereals or their stored grain products. Fungal colonization of the living crop stunts growth and reduces yields. However, once in the food chain, toxic secondary metabolites known as mycotoxins pose the most risk. Mycotoxins affect human and animal health, causing serious adverse effects and even death. Chronic ingestion causes growth failure in children, immunodeficiency disease, and liver cancer in adults. Mycotoxins are often unaffected by food processing and so continue along the food chain. Control measures are in place in many countries including the European Union and North America, requiring regular food analysis for maximum permissible levels for mycotoxins. Barley is a common crop used in the beer malting industry. It is the second most abundant crop in the Czech Republic and, as with many areas of Europe, favorable weather conditions for Fusarium growth are commonly encountered there. In addition to posing a human health risk, Fusarium species also affect the production of beer. Mycotoxins are not destroyed by the brewing process, and contamination can decrease the malting quality of the crop. Traditionally, enzyme-linked immunosorbent assays (ELISA) are used to monitor mycotoxin levels in cereals. However, these rely on suitable antibodies and are not suitable for efficient screening since contamination by several different mycotoxins is common. Bĕláková and co-researchers¹ used high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC LC-MS/MS) to analyze fusarium mycotoxins in Czech barley crop samples collected over four years. They homogenized and lyophilized (freeze-dried) samples, vacuum drying the preparations before chromatographic separation and subsequent quantification using a Thermo Scientific ion trap LCQ Advantage mass spectrometer. Using the assay, the researchers quantified levels of deoxynivalenol (DON), zearalenone (ZON), T-2 toxin and HT-2 toxin against calibration curves created from serial dilutions of commercial mycotoxin preparations. The team also assessed recovery of mycotoxins from samples spiked with the commercial preparations, running tests in triplicate for each analyte. Assay characteristics showed limits of detection (LODs) between 0.3 and 1.5µg/kg and limits of quantification (LOQs) lying between 1 to 5µg/kg. The researchers reported recovery rates between 71.5 and 103% for the spiked samples. Over 300 samples of Czech malting barley were assayed. Bĕláková et al. found that all samples showed some degree of contamination, with 78 containing multiple mycotoxins. Only 5% of samples contained all mycotoxins. Results were similar to other reported studies and showed variation with recorded weather conditions. Reassuringly, only one sample showed contamination above European Union permissible levels for DON. Reference