Survey of Alternaria toxin contamination in food from the German market, using a rapid HPLC-MS/MS approach

Abstract

A HPLC-MS/MS-based method for the quantification of nine mycotoxins produced by fungi of the genus Alternaria in various food matrices was developed. The method relies on a single-step extraction, followed by dilution of the raw extract and direct analysis. In combination with an analysis time per sample of 12 min, the sample preparation is cost-effective and easy to handle. The method covers alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), altenuene (ALT), iso-altenuene (isoALT), tentoxin (TEN), altertoxin-I (ATX-I), and the AAL toxins TA1 and TA2. Some Alternaria toxins which are either not commercially available or very expensive, namely AOH, AME, ALT, isoALT, and ATX-I, were isolated as reference compounds from fungal cultures. The method was extensively validated for tomato products, bakery products, sunflower seeds, fruit juices, and vegetable oils. AOH, AME, TeA, and TEN were found in quantifiable amounts and 92.1% of all analyzed samples (n = 96) showed low level contamination with one or more Alternaria toxins. Based on the obtained results, the average daily exposure to Alternaria toxins in Germany was calculated.

Tracking emerging mycotoxins in food: development of an LC-MS/MS method for free and modified Alternaria toxins

“…Compounds with genotoxic properties, AOH and AME, were found in about half of the tomato sauce samples. The concentrations determined are in a similar range as published in other recent studies [29, 31, 53]. To the best of our knowledge, the masked mycotoxin AOH-9-Glc was identified and quantified for the first time in any food matrix.…”

“…Walravens et al [30] investigated 10 Alternaria toxins (including the four modified toxins AOH-3-Glc, AOH-3-S, AME-3-Glc, AME-3-S) reaching limits of detection (LOD) between 0.5 and 5 ng/g in cereal-based foodstuffs and in a later publication between 3 and 18.3 ng/g in tomato products [29]. More recent studies included further toxins such as the AAL toxins TA1 and TA2, isoALT [31–33], and altertoxins [5, 34]. Using solid-phase extraction, LODs between 0.1 and 0.6 ng/mL were achieved for 12 Alternaria toxins in wine and fruit and vegetable juices [5].…”

“…Isotopically labeled internal standards can be used to ensure the performance of quantitative methods and were employed in first applications [30, 35, 36]. The most frequently analyzed food matrices were cereal- and tomato-based products, fruit juices, wine, maize, and sunflower seeds [4, 20, 26, 27, 29, 31–34, 37–40]. …”

AlternariaMycotoxins in Food and Feed: An Overview

“…Consequently, Alternaria mycotoxins were detected in cereals and derived products [46,[57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76], feed [74,[109][110][111][112][113], dairy products [114], grapes and by-products [27,77,115], tomatoes and derived products [31,47,77,81,106,113], nuts and by-products [102,116], spices [117], soybeans [76,116,118], sunflower seeds [85,104,107], vegetables [27,101], vegetable oils [105], strawberries …”

“…These were followed by Alternaria toxins ATXs included in 16% of the analyzed studies, whereas only a few publications reported other compounds such as macrosporin (9%), monocerin, ALN, AALs, and infectopyrone (all <3%). Notably, limited information was found about pyrenochaetic acid A (PyA), alternarienonic acid (AIA), and alloTeA and isoALT, recently reported in food samples for the first time [31,105] and metabolites such as AOH3S, AOH3G, AME3S, and AME3G [47,69]. In this way, AOH, AME, TeA, and TEN have been shown to occur in food samples frequently [82,97,108], while the occurrence of ALT, isoALT, ATX-I, and AAL toxins is of much lower incidence, mainly due to shortcomings in current analytical methodologies.…”