Development of a LC-MS/MS method for the analysis of enniatins and beauvericin in whole fresh and ensiled maize

Multi-mycotoxin analysis in eggs using a QuEChERS-based extraction procedure and ultra-high-pressure liquid chromatography coupled to triple quadrupole mass spectrometry

A reliable and rapid method has been developed for the determination of 10 mycotoxins (beauvericin, enniatin A, A1, B1, citrinin, aflatoxin B1, B2, G1, G2 and ochratoxin A) in eggs at trace levels. Ultra-high-pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) has been used for the analysis of these compounds in less than 7 min. Mycotoxins have been extracted from egg samples using a QuEChERS-based extraction procedure (Quick, Easy, Cheap, Effective, Rugged and Safe) without applying any further clean-up step. Extraction, chromatographic and detection conditions were optimised in order to increase sample throughput and sensitivity. Matrix-matched calibration was used for quantification. Blank samples were fortified at 10, 25, 50 and 100 μg kg(-1), and recoveries ranged from 70% to 110%, except for ochratoxin A and aflatoxin G1 at 10 μg kg(-1), and aflatoxin G2 at 50 μg kg(-1). Relative standard deviations were lower than 25% in all the cases. Limits of detection ranged from 0.5 μg kg(-1) (for aflatoxins B1, B2 and G1) to 5 μg kg(-1) (for enniatin A, citrinin and ochratoxin A) and limits of quantification ranged from 1 μg kg(-1) (for aflatoxins B1, B2 and G1) to 10 μg kg(-1) (for enniatin A, citrinin and ochratoxin A). Seven samples were analyzed and aflatoxins B1, B2, G1, G2, and beauvericin were detected at trace levels.

Isolation and purification of enniatins A, A(1), B, B(1), produced by Fusarium tricinctum in solid culture, and cytotoxicity effects on Caco-2 cells

Enniatins (ENs) are antibiotic compounds of hexadepsipeptidic structure produced by several strains of Fusarium spp. The ENs A, A(1), B, B(1) were purified from extracts of Fusarium tricinctum grown on a solid medium of corn, by a low pressure liquid chromatography (LPLC) on reverse phase of Amberlite XAD-7 followed by semipreparative LC. The purity and the structure of the isolated compounds were confirmed by LC-MS/MS. The technique of the purification of the fungal extract enabled complete separation of the ENs A, A(1), B, B(1) with a mean purity of 97% for all the compounds. The cytoxicity of the ENs was tested in the cell lines of human origin (epithelial colorectal adenocarcinoma cells, Caco-2) by MTT assays. Only EN A(1) and B(1) evoked toxicity at the tested concentrations. The inhibitory concentration (IC(50)) for EN A(1) on Caco-2 cells was 12.3 microM, whereas the IC(50) produced by the EN B(1) was 19.5 microM. This study indicates that ENs, fungal metabolites that are commonly found in corn and in general in product composed by corn, may have a toxic potential for human health.

Antifungal effects of the bioactive compounds enniatins A, A(1), B, B(1)

To produce enniatin (ENs), Fusarium tricinctum CECT 20150 was grown in a liquid medium of potato (PDB), being mycotoxin purified by high performance liquid chromatography (HPLC) with a reverse phase semipreparative column using a mobile phase of acetonitrile/water using gradient condition. The purity of the ENs fractions was verified by analytical HPLC and LC/MS-MS. The pure fractions of ENs were utilized to study the biological activity on several mycotoxigenic moulds as Fusarium verticilloides, Fusarium sporotrichioides, Fusarium tricinctum, Fusarium poae, Fusarium oxysporum, Fusarium proliferatum, Beauveria bassiana, Trichoderma harzianum, Aspergillus flavus, Aspergillus parasiticus, Aspergillus fumigatus, Aspergillus ochraceus and Penicillium expansum. The results obtained demonstrated that in several antibiograms, ENs induced the inhibition of the grown microorganisms tested.

Antibacterial effect of the bioactive compound beauvericin produced by Fusarium proliferatum on solid medium of wheat

To obtain the bioactive compound beauvericin (BEA), Fusarium proliferatum CECT 20569 was grown on a solid medium of wheat, utilizing the technique of the solid state fermentation (SSF), being this mycotoxin purified by high performance liquid chromatography (HPLC) with a reverse phase semi-preparative column using as the mobile phase acetonitrile/water in gradient condition. The purity of the BEA was verified by analytical HPLC and liquid chromatography tandem mass spectrometry (LC/MS-MS). The pure fractions of BEA were utilized to determinate the antibiotic effects on several bacterial strains that are considered normally pathogens of the intestinal tract as: Escherichia coli, Enterococcus faecium, Salmonella enterica, Shigella dysenteriae, Listeria monocytogenes, Yersinia enterocolitica, Clostridium perfringens, Pseudomonas aeruginosa and Staphylococcus aureus.

Multi-mycotoxin analysis of maize silage by LC-MS/MS

This paper describes a method for determination of 27 mycotoxins and other secondary metabolites in maize silage. The method focuses on analytes which are known to be produced by common maize and maize-silage contaminants. A simple pH-buffered sample extraction was developed on the basis of a very fast and simple method for analysis of multiple pesticide residues in food known as QuEChERS. The buffering effectively ensured a stable pH in samples of both well-ensiled maize (pH < 4) and of hot spots with fungal infection (pH > 7). No further clean-up was performed before analysis using liquid chromatography-tandem mass spectrometry. The method was successfully validated for determination of eight analytes qualitatively and 19 quantitatively. Matrix-matched calibration standards were used giving recoveries ranging from 37% to 201% with the majority between 60% and 115%. Repeatability (5-27% RSD(r)) and intra-laboratory reproducibility (7-35% RSD(IR)) was determined. The limit of detection (LOD) for the quantitatively validated analytes ranged from 1 to 739 microg kg(-1). Validation results for citrinin, fumonisin B(1) and fumonisin B(2) were unsatisfying. The method was applied to 20 selected silage samples and alternariol monomethyl ether, andrastin A, alternariol, citreoisocoumarin, deoxynivalenol, enniatin B, fumigaclavine A, gliotoxin, marcfortine A and B, mycophenolic acid, nivalenol, roquefortine A and C and zearalenone were detected.

Overview of analytical methods for beauvericin and fusaproliferin in food matrices

In recent years consumers and the scientific community have become increasingly interested in food safety, making it a major focus among the objectives of the international institutions responsible for food safety monitoring, e.g. the European Union or the EFSA. Aspects attracting much attention are the colonization of food by microscopic fungi which, under aerobic conditions, produce toxic secondary metabolites known as mycotoxins, and the accumulation of these toxins in the food chain. Numerous studies of surveillance, detoxification, prevention, and toxicological aspects reported in the literature mostly concentrate on major mycotoxins such as aflatoxins, ochratoxin A, trichothecenes, and fumonisins; studies on toxic secondary metabolites of mycotoxins are less common or are only just beginning. Among the molecules of interest, the family of beauvericin and fusaproliferin is certainly the most interesting. The objective of this review is to summarize reported data and the methods used to extract and quantify beauvericin and fusaproliferin in food matrices.

What about the 'other' Fusarium mycotoxins?

Most Fusarium species are capable of producing mycotoxins that may cause adverse effects on human or animal health. The most commonly studied Fusarium mycotoxins include trichothecenes, zearalenone and fumonisins. However, it seems that nearly all of the most prevalent Fusarium species infecting grains are also capable of producing other toxic metabolites. The existing studies, although exiguous, have clearly demonstrated that other toxic metabolites of Fusarium spp. are also present in our foods and feeds, occasionally at very high levels. It is apparent that since mycotoxins, including these 'other' metabolites, are natural toxins, they cannot be completely eliminated from food and feed chains. However, scientific studies are needed to determine their true significance. Thus, the mechanism and level of toxicity as well as presence and concentration levels will have to be fully clarified. In this paper, we briefly review the prevalence of the dominant Fusarium species contaminating maize and small-grain cereals worldwide, and the current knowledge on the biological activity as well as the natural occurrence of their selected less-known toxic metabolites. Additionally, the significance of these 'other' Fusarium mycotoxins is discussed.