The aim of this review is to give a comprehensive overview of the current knowledge on plant metabolites of mycotoxins, also called masked mycotoxins. Mycotoxins are secondary fungal metabolites, toxic to human and animals. Toxigenic fungi often grow on edible plants, thus contaminating food and feed. Plants, as living organisms, can alter the chemical structure of mycotoxins as part of their defence against xenobiotics. The extractable conjugated or non-extractable bound mycotoxins formed remain present in the plant tissue but are currently neither routinely screened for in food nor regulated by legislation, thus they may be considered masked. Fusarium mycotoxins (deoxynivalenol, zearalenone, fumonisins, nivalenol, fusarenon-X, T-2 toxin, HT-2 toxin, fusaric acid) are prone to metabolisation or binding by plants, but transformation of other mycotoxins by plants (ochratoxin A, patulin, destruxins) has also been described. Toxicological data are scarce, but several studies highlight the potential threat to consumer safety from these substances. In particular, the possible hydrolysis of masked mycotoxins back to their toxic parents during mammalian digestion raises concerns. Dedicated chapters of this article address plant metabolism as well as the occurrence of masked mycotoxins in food, analytical aspects for their determination, toxicology and their impact on stakeholders.

Mycotoxin contamination of cereals and related products used for feed can cause intoxication, especially in farm animals. Therefore, efficient analytical tools for the qualitative and quantitative analysis of toxic fungal metabolites in feed are required. Current methods usually include an extraction step, a clean-up step to reduce or eliminate unwanted co-extracted matrix components and a separation step with suitably specific detection ability. Quantitative methods of analysis for most mycotoxins use immunoaffinity clean-up with high-performance liquid chromatography (HPLC) separation in combination with UV and/or fluorescence detection. Screening of samples contaminated with mycotoxins is frequently performed by thin layer chromatography (TLC), which yields qualitative or semi-quantitative results. Nowadays, enzyme-linked immunosorbent assays (ELISA) are often used for rapid screening. A number of promising methods, such as fluorescence polarization immunoassays, dipsticks, and even newer methods such as biosensors and non-invasive techniques based on infrared spectroscopy, have shown great potential for mycotoxin analysis. Currently, there is a strong trend towards the use of multi-mycotoxin methods for the simultaneous analysis of several of the important Fusarium mycotoxins, which is best achieved by LC-MS/MS (liquid chromatography with tandem mass spectrometry). This review focuses on recent developments in the determination of mycotoxins with a special emphasis on LC-MS/MS and emerging rapid methods.

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This paper describes the composition of walnut oils obtained from nuts collected from seven countries that are major suppliers of walnut oil. Oils were extracted from the nuts using small-scale industry pressing equipment and analyzed using standard methods for fatty acids, fatty acids in the triacylglycerol 2-position, tocopherols and tocotrienols, triacylglycerols, sterols, steradienes, and iodine value. Values for the composition of the sterols, triacylglycerols, fatty acids, iodine value, and tocopherol composition were generally in good agreement with the results of previous similar surveys. Tocotrienols were not detected in any sample. Steradienes (stigmastadiene, campestadiene, stigmastatriene, and campestatriene) were not detected in any oil.

A total of 1709 samples of plant-derived food products, mainly produced in Europe, were analysed for tropane alkaloids (TAs). The samples, of which 27.4% came from organic production, were collected from retail stores, ). Samples analysed for the presence of 24 TAs comprised 268 single component flours (buckwheat, millet, corn), 260 cereal-based foods for young children age 6-36 months (breakfast cereals, biscuits and other cereal-based foods), 219 breakfast cereals, 164 biscuits and pastry, 114 bread, 81 pasta, 121 dry (herbal) teas, 78 legumes and stir-fry mixes. Samples analysed for six calystegines comprised 308 potato, 90 aubergine and six bell peppers. All samples were analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Two methods were developed and validated in house and were considered fit for purpose. The limits of quantification for the various food groups were, depending on the type of TA, 0.0067-0.0333 μg/L for tea infusion, 0.5-5 μg/kg in cereal-based products, herbal tea and vegetable products, and 1-2.5 mg/kg in potatoes and aubergines. One or more TAs were detected in 21.3% of single component flours, 20.0% of cereal-based foods for young children age 6-36 months, 6.8% of breakfast cereals, 14.6% of biscuits and pastry, 15.8% of bread, 70.2% of dry (herbal) tea, 26.2% of legumes and stir-fry mixes, 100% of potatoes and 92.7% of aubergines. No TAs were detected in pasta. The highest mean TA concentration was detected in cereal-based meals for children (130.7 µg/kg), and the maximum TA concentration of was detected in a dry herbal tea sample (4357.6 µg/kg). Atropi ne and scopolamine were the most frequently detected TAs with a maximum sum concentration of 428.5 µg/kg in a dry herbal tea.

This paper describes the composition of 30 grape-seed oils obtained from France, Italy, and Spain during 2002-2003. Oils were extracted from the seeds using small-scale industrial solvent extraction equipment and analyzed in their unrefined state using standard methods for fatty acids, fatty acids in the triacylglycerol 2-position, tocopherols and tocotrienols, triglycerides, sterols, steradienes, and iodine value. Values for the composition of the sterols, triglycerides, fatty acids, iodine value, and tocopherol composition were generally in good agreement with the results of previous similar surveys. Steradienes (stigmastadiene, campestadiene, stigmastatriene, and campestatriene) were detected in the oil and were probably formed from sterols during the extraction process.

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The purpose of this paper is to summarize the most relevant and recent information available on ergot alkaloids. This includes information about their occurrence, toxicity, chemistry, statutory limits, and their significance in feed and food. Recently, in 2005, the European Food Safety Authority (EFSA) concluded that validated analytical methods for the quantification of ergot alkaloids in feed materials are needed. For that reason, the major focus of the present paper is to report on the latest developments for the determination of major ergot alkaloids and their epimers in cereals and cereal-derived products. Information about the stability and the availability of calibrants, sampling issues, extraction and clean-up strategies, and a variety of final separation and detection techniques is provided. The recently developed liquid chromatography-tandem mass spectrometric methods (LC-MS/MS) for the simultaneous quantification and identification of ergot alkaloids are given special consideration.