Abstracts (WP7)

Immunochemical methods of mycotoxins analysis

The review is devoted to comparative characterization of immunochemical methods of detection of mycotoxin, which belongs to one of the priority groups of the food contaminants. It has been shown that the high specificity and the possibility of mycotoxin detection in low concentrations combined with existent diverse equipment allow for considering the immunochemical methods of analysis to be the most promising for wide practical application. The analytical characteristics of the existent developments are presented; the merits and demerits of the different kinds of immunoanalytical systems are compared.

Widespread Occurrence of the Mycotoxin Fumonisin B2 in Wine

Fumonisins are important mycotoxins because they are suspected to cause human and animal toxicoses by the consumption of contaminated corn-based food and feeds. However, with the discovery of fumonisin production in grapes by Aspergillus niger, wine may also be a fumonisin containing commodity. In the present study, we have developed a simple and quantitative cation exchange-based purification method for the subsequent isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of fumonisins in wine. A comparative study of seven different solid-phase extraction (SPE) columns showed that polymeric mixed-mode reversed-phase (RP) cation-exchange columns were superior to classic silica-based cation and mixed-mode cation-exchange columns. A total of 77 wine samples from 13 countries were subsequently tested, and surprisingly, 18 (23%) were found to contain fumonisin B2 in the range of 1-25 μg/L. These findings were further confirmed by immunoaffinity purification and re-analysis of the positive cation-exchanged extracts.

Natural occurrence of fumonisin B2 in red wine from Italy

The potential risk of exposure to fumonisin B2 (FB2) in the grape-wine chain has recently been revealed after a report of Aspergillus niger in grapes and its ability to produce FB2 and FB4. The occurrence of these two fumonisins in wine was investigated by LC/MS/MS in 51 market samples (45 red, five white and one rose´ wine) produced in various Italian regions. Nine samples of red wine were found to be contaminated by fumonisin B2 at levels ranging from 0.4 to 2.4 ng/ml, while FB4 was not detected in any of the tested samples. This is the first report on the natural occurrence of FB2 in wine, indicating that, although at low levels, there is a potential risk of FB2 exposure for the wine-consumer.

Occurrence of free and conjugated Fusarium mycotoxins in cereal based food

A collection of 84 cereal-based food products in 25 composites, including beer, was screened for the presence of deoxynivalenol, zearalenone, and their respective metabolites deoxynivalenol-3-glucopyranoside, 3-acetyl-deoxynivalenol, zearalenol-4-glucopyranoside, alpha-zearalenol, beta-zearalenol, alpha-zearalenol-4-glucopyranoside, beta-zearalenol-4-glucopyranoside, and zearalenone-4-sulfate. The most abundant analyte was zearalenone-4-sulfate, which was found in 13 composites, albeit in low concentrations. Furthermore, deoxynivalenol was detected in eight, zearalenone in seven, and deoxynivalenol-3-glucopyranoside in two composites. None of the remaining six analytes was found in any matrices, which suggests that, if at all present, the concentrations of these latter metabolites are very low and, hence, do not impose any danger to consumers. The highest mycotoxin content was found in bran flakes with 254 ng g(-1) deoxynivalenol, 6 ng g(-1) zearalenone-4-sulfate, and 44 ng g(-1) zearalenone.

Direct quantification of deoxynivalenol glucuronide in human urine as biomarker of exposure to the Fusarium mycotoxin deoxynivalenol.

The direct quantification of deoxynivalenol glucuronide (DON-GlcA) by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and its application as a biomarker of exposure to the Fusarium mycotoxin deoxynivalenol (DON) is reported. Usually, DON exposure is estimated from dietary average intakes or by measurement of the native toxin in urine after enzymatic hydrolysis with β-glucuronidase. These methods are time-consuming, expensive, and fail to determine the ratio of DON to DON-GlcA in a simple one-step procedure. One of the main reasons for the use of indirect methods is the unavailability of DON-GlcA standards. Consequently, DON-3-O-glucuronide (D3GlcA) was synthesized and used to develop a method allowing quantification of both DON and D3GlcA by a simple "dilute and shoot" approach without the need for any cleanup. Limit of detection and apparent recovery of D3GlcA was 3 μg l(-1) and 88%, respectively. The identity of D3GlcA in human urine was confirmed by comparison with LC-MS/MS measurements of the synthetically produced D3GlcA standard which was also used for external calibration. The applicability of the method was demonstrated through the analysis of urine samples obtained from a volunteer during regular and cereal-restricted diet, respectively. In regular-diet urine samples, D3GlcA was quantified in concentrations >30 μg l(-1) by this approach.

Bioaccessibility of Deoxynivalenol and its natural co-occurrence with Ochratoxin A and Aflatoxin B1 in Italian commercial pasta

Cereals products for direct human consumption are rarely contaminated by moulds, unlike raw materials,which are often infected, either in the field or during storage.
In this study, 27 samples of dried pasta characterised by size, packaging and marketing intended for young children consumption were collected and analysed by liquid chromatography (LC) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) for Deoxynivalenol (DON), Ochratoxin A (OTA) and Aflatoxin B1 (AFB1) determination.
The samples that showed the highest amounts of one of the mycotoxins were cooked for 10 min, digested with an in vitro gastrointestinal protocol and bioaccessibility values were calculated. Seven of the 27 samples exceeded from 120% to 225% the legal limit of 200 lg/kg for DON fixed for processed cereal-based baby foods by an European Regulation; all the collected samples were under the OTA legal limit (0.05 lg/kg) fixed by the European Regulation and no sample was contaminated by AFB1 over the instrumental limit of detection of 0.10 lg/kg. The mean value of gastric bioaccessibility verified for the DON resulted of 23.1%, whereas mean duodenal bioaccessibility was 12.1%.





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