Study of the natural occurrence of T-2 and HT-2 toxins and their glucosyl derivatives from field barley to malt by high-resolution Orbitrap mass spectrometry

Authors: LATTANZIO, VERONICA - National Research Council - Italy; CIASCA, BIANCAMARIA - National Research Council - Italy; TERZI, VALERA - Agricultural Research Council (CRA); GHIZZONI, ROBERTA - Agricultural Research Council (CRA); McCormick, Susan; PASCALE, MICHELANGELO - National Research Council - Italy

Submitted to: Food Additives & Contaminants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2015
Publication Date: 6/1/2015
Publication URL: https://handle.nal.usda.gov/10113/62208
Citation: Lattanzio, V.M.T., Ciasca, B., Terzi, V., Ghizzoni, R., McCormick, S.P., Pascale, M. 2015. Study of the natural occurrence of T-2 and HT-2 toxins and their glucosyl derivatives from field barley to malt by high-resolution Orbitrap mass spectrometry. Food Additives & Contaminants: Part A. 32(10):1647-1655.

Interpretive Summary: T-2 toxin is a trichothecene mycotoxin produced when the fungus Fusarium infects small grains including barley. Ingestion of T-2 toxin contaminated grain can cause diarrhea, hemorrhaging, and feed refusal. Plants infected with mycotoxin-producing fungi form sugar derivatives of toxins. These sugar derivatives, sometimes called masked mycotoxins, are a potential food safety concern because they are not detected by standard approaches and could potentially be converted back to the parent toxin during digestion or food processing. Development of methods to assess the occurrence of these toxins in cereals and the risk posed by consuming contaminated foods have been aided by the recent availability of a masked T-2 toxin produced in the laboratory. The amount of trichothecene mycotoxins and masked mycotoxins present in naturally infected grain were measured. In unprocessed barley, the amounts of T2 and HT-2 toxins ranged from 4 to 340 migrograms per kilogram and the amounts of T2 and HT2-glucosides ranged from 0 to 163 micrograms per kilogram. This study found that there was a significant reduction in the total amount of these toxins after barley is cleaned and malted.

Technical Abstract: This paper reports a new method for the determination of T-2 and HT-2 toxins and their glucosylated derivatives in cereals, and some survey data aimed at obtaining more comprehensive information on the co-occurrence of T-2 and HT-2 toxins and their glucosylated derivatives in naturally contaminated cereal samples. For these purposes, barley samples originating from a Northern Italian area were analysed by LC-HRMS for the presence of T-2, HT-2 and relevant glucosyl derivatives. Quantitative analysis of T-2 and HT-2 glucosides was performed for the first time using a recently made available standard of T-2 glucoside. The glucosyl derivative of HT-2 was detected at levels up to 163 µg kg–1 in 17 of the 18 analysed unprocessed barley grains, whereas the monoglucosyl derivative of T-2 toxin was detected in only a few samples and at low µg kg–1 levels. The ratio between glucosylated toxins (sum of T-2 and HT-2 glucosides) and native toxins (sum of T-2 and HT-2) ranged from 2% to 283%. Moreover, taking advantage of the possibility of retrospective analysis of full-scan HRMS chromatograms, samples were also screened for the presence of other type-A trichothecenes, namely neosolaniol, diacetoxyscirpenol and their monoglucosyl derivatives, which were detected at trace levels. A subset of nine different samples was subjected to micro-maltation in order to carry out a preliminary investigation on the fate of T-2, HT-2 and relevant glucosides along the malting process. Mycotoxin reduction from cleaned barley to malt was observed at rates ranging from 4% to 87%.