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PubMed2005

Mould contamination and co-occurrence of mycotoxins in maize grain in Croatia.

Maize grain samples (n=15) collected during the autumn of 2002 were analyzed for the presence of moulds and mycotoxins fumonisin B1 (FB1), fumonisin B2 (FB2), zearalenone (ZEA), and ochratoxin A (OTA). Mycological analysis showed that all samples were contaminated with Fusarium spp. and Penicillium spp., while Aspergillus spp. were found in 5 samples. F. proliferatum and F. verticilloides, the producers of fumonisins, were found in 14 and 8 samples, respectively, while F. graminearum, the producer of ZEA, was present in all samples. The most frequent mycotoxins were FB1 (15/15) and ZEA (12/15), followed by OTA (7/15), while FB2 was found in only two samples. Seven samples were contaminated with two mycotoxins, seven with three, and one sample with only one mycotoxin. The concentrations (mean+/-SD) of FB1, ZEA, and OTA in positive samples were 459.5+/-314.6, 1.70+/-0.80, and 1.40+/-0.55 microg kg-1, respectively, and the concentrations of FB2 in two samples were 68.4 and 3084.0 microg kg-1. In general, such low mycotoxin concentrations are not a significant source of exposure to humans, but they may contribute to exposure from other commodities. A few samples with extreme values indicate that strict control is needed.

Aspergillus↗

PubMed1991

Risk assessment to humans of mycotoxins in animal-derived food products.

This paper addresses approaches for assessing potential human health hazards from the presence of natural toxicants, such as mycotoxins, in animal food products. At high levels in feed these mycotoxins may cause loss or illness of farm animals, through development of animal toxicoses, such as aflatoxicosis. At lower levels in feed these mycotoxins may have no apparent effect on livestock production, but their residues and related substances may move up the food chain. This indirect intake of mycotoxins and related substances from the consumption of animal food products may pose a health hazard to humans. These health hazards are compared to the possible health hazards from the direct intake by humans of cereal and other food crops that may contain mycotoxins.

Animal Feed↗

PubMed1979

Simultaneous extraction and fractionation and thin layer chromatographic determination of 14 mycotoxins in grains.

A simple, systematic analytical method for multiple mycotoxins was developed for detecting 14 mycotoxins; aflatoxins B1, B2, G1, and G2, sterigmatocystin, T-2 toxin, diacetoxyscirpenol, neosolaniol, fusarenon X, zearalenone, ochratoxin A, citrinin, luteoskyrin, and rugulosin. These mycotoxins were extracted with 20% H2SO4-4% KCl-acetonitrile (2 + 20 + 178), defatted with isooctane, and transferred to chloroform. The chloroform extract was cleaned up by silica gel column chromatography; the first 10 toxins were eluted with chloroform-methanol (97 + 3) and the remaining 4 toxins with benzene-acetone-acetic acid (75 + 20 + 5). Each fraction was analyzed by thin layer chromatography for the final determination. The method has been applied to polished rice, rough rice, corn, wheat, and peanuts as an analytical screening procedure. The detection limits in these commodities ranged from 10.00 to 800.0 microgram/kg, depending on the mycotoxin, but all limits were superior to those obtained for the individual mycotoxins by using other methods.

Arachis↗

PubMed1982

Influence of mycotoxins on protein and amino acid utilization.

The interrelationships between mycotoxins and the utilization of dietary protein are reviewed. Acute aflatoxicosis is characterized by reduced growth and fatty infiltration of the liver. Studies with poultry, swine, and monkeys have shown that supplements of dietary protein beyond normal requirements can overcome these conditions. High-protein diets, however, have been shown to promote hepatoma characteristic of chronic aflatoxicosis in rats. Aflatoxin interferes with utilization of dietary protein by inhibiting synthesis of DNA, RNA, and protein. High-protein diets promote the metabolism of aflatoxin by the hepatic microsomal drug-metabolizing enzyme system. The Fusarium mycotoxin zearalenone increases membrane permeability and promotes uterine synthesis of DNA, RNA, and protein. Supplements of dietary protein overcome growth reduction due to zearalenone and reduce the metabolic half-life of the toxin by promoting urinary excretion of free, unmetabolized zearalenone in the rat. The trichothecene mycotoxins disrupt normal protein metabolism by inactivating the ribosomal cycle. Protein supplements appear to have little effect on trichothecene mycotoxicoses. Most mycotoxins impair utilization of dietary protein. The effectiveness of protein supplements in overcoming mycotoxicoses will depend on the mycotoxin in question.

Aflatoxins↗

PubMed1995

Analysis of mycotoxins in food and feed: certification of DON in wheat and maize.

Worldwide there are either statutory limits or in some instances advisory guidelines for the maximum levels of mycotoxins in foods and feeds. These limits which have been agreed for the protection of human health and as standards for trade are often set at surprisingly low levels in view of both the problems of sampling and the abundant evidence of the difficulties of mycotoxin analysis, particularly so when approaching the limits of detection. Improved methodology for mycotoxins and improvements in performance even of expert laboratories have, however, been achieved through intercomparison exercises organised by the EC Measurement and Testing programme (formerly BCR). On a wider scale, participation in proficiency testing through schemes such as the UK Food Analysis Performance Assessment Scheme (FAPAS) have indicated that between 10 and 40% of laboratories experience difficulties in obtaining satisfactory results in monitoring mycotoxins. Reference materials provide an important means of checking method performance. BCR has made a unique contribution in the production and certification of maize and wheat reference materials naturally contaminated with the Fusarium mycotoxin 4-deoxynivalenol (DON), which has now been available for purchase for some 2 years.

Calibration↗

PubMedDate not supplied

Effects of macrocyclic trichothecene mycotoxins on the murine immune system.

Macrocyclic trichothecenes are a class of mycotoxins, some of which exhibit substantial antileukemic properties. These compounds vary in their toxicity by approximately 100 fold and are suspected immunotoxins. We studied 11 of these mycotoxins: roritoxin B, myrotoxin B, roridin A, verrucarin A, 16-hydroxyverrucarin A, verrucarin J, baccharinoid B12, roridin D, roridin E, baccharinoid B4 and baccharinoid B5 for their immunotoxicity in CD-1 mice. An equitoxic dose was prepared in 1% DMSO in saline and administered i.p. at half the LD50. Organ weights, WBC, RBC, differentials of blood cell counts, blastogenesis of splenic lymphocytes in response to concanavalin A (Con A), lipopolysaccharide (LPS), phytohemagglutinin (PHA) and pokeweed mitogen (PWM), and mixed lymphocyte reaction (MLR) were studied on day 4 after administration of each mycotoxin. Organ weights showed significant differences between the controls and the baccharinoids with a decrease in spleen weight in baccharinoid B12 and an increased liver weight in B4 and B5 treated animals. Administration of myrotoxin B, roridin A, verrucarin J and roridin E had total WBC counts statistically different from controls, while mice administered myrotoxin B shoed a decrease in numbers of RBC. Differentials of WBC were unremarkable regardless of the mycotoxin. Roritoxin B and baccharinoid B5 increased Con A stimulation of splenic lymphocytes. Roridin A and baccharinoid B12 increased LPS stimulation of splenic lymphocytes while baccharinoid B5 decreased the LPS response. Stimulation of splenic lymphocytes with PHA was significantly increased by roridin A and baccharinoid B5. Stimulation of splenic lymphocytes with PWM was not altered significantly by any mycotoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Monoclonal antibody technology for mycotoxins.

Specific monoclonal antibodies (MABs) against aflatoxins, ochratoxin A, zearalenone, diacetoxyscirpenol and T-2 toxin have been prepared in various laboratories by the application of hybridoma technology to mycotoxins. These antibodies can be selected for sensitivity, reduced cross-reactivity, reliability and ease of production. When a suitable antibody is chosen it can then be used in a rapid immunological method such as an enzyme-linked or radio-immunoassay or immunoaffinity chromatography system. These assays have a lower limit of mycotoxin detection in the ng/ml range and have been applied to the determination of mycotoxins in samples such as maize, peanuts, peanut butter, milk and porcine kidneys. Using these immunoassay techniques, sample preparation has generally been simplified to a matter of solvent extraction of mycotoxins from the sample followed by dilution; under these conditions, levels of 1-5ug of mycotoxins/kg of sample can be found. The application and advantages of MABs to mycotoxins and the use of these antibodies in various assay techniques is discussed.

Journal Article↗

PubMed2004

Influence of agricultural practices on fusarium infection of cereals and subsequent contamination of grain by trichothecene mycotoxins.

Fusarium head blight (FHB) of small grain cereals and ear rot in maize are significant diseases across the world. Infection can not only result in reduced yield as a result of shrunken grains but also result in reduced milling and malting quality and the contamination of grains with mycotoxins. Mycotoxins are hazardous to animal and human health. Therefore, guidelines and legislation are in place, or under consideration, in most countries to protect consumers and animal welfare. As fusarium mycotoxins are produced within the growing crop, it is important to understand how agricultural practices affect mycotoxin contamination of grain. Such information could then be used to determine guidelines on "Good Agricultural Practice" (GAP) to minimise the mycotoxin contamination of cereal products. Evidence is provided to show the importance of choice of cultivar, crop rotation, soil cultivation, fertiliser and the chemical and biological control of insects, weeds and fungi.

Agriculture↗

PubMed2004

Effects of grain sampling procedures on fusarium mycotoxin assays in wheat grains.

Fusarium mycotoxins are increasingly studied agronomically, chemically, and pathologically in the context of food safety, as a means of preventing new major health crises. Reliable mycotoxin techniques and sampling procedures are required for assessment of the effects of different sources of variation on grain mycotoxin content in agronomic experiments. Analyses were performed with the aim of formulating guidelines for grain sampling to increase the reliability of grain mycotoxin measurement in agronomic experiments. Two toxins in wheat samples, deoxynivalenol and nivalenol, were targeted. With a nested linear mixed model, it was estimated that the uncertainty of nivalenol determination was low (+/-15 microg/kg), whereas that for deoxynivalenol determination was higher (+/-38 microg/kg). It was also found that grinding of the grain decreased the variability of the results. Moreover, despite the heterogeneity in grain mycotoxin content across a given field, it was shown that heads can be harvested manually for agronomic experiments provided that sampling is representative (evenly distributed over the entire plot area). Finally, delaying the assay until after harvest was found to affect the results obtained and should therefore be avoided.

Edible Grain↗

PubMed2000

[Emerging mycotoxin control. Current limits and regulations].

Emerging mycotoxins are of a great importance due to their high occurrence in foods and feeds and their implication in pathologies. There is a need to control them both in pre- and post-harvest. However, the increasing drawbacks of chemical decontamination methods, makes the use of preventive methods more attractive. These are based on avoiding growth of mycotoxigenic fungi and mycotoxin accumulation in these substrates (by using reduced aw levels, and modifying other storage conditions) and the early detection of these mycotoxins by using simple and fast analysis techniques. At the same time, it is important to know the effect that industrial processing has on mycotoxin concentration in foods and feeds, because it may reduce the toxin content. Finally, maximum limits of mycotoxin concentration should be established for both foods and feeds.

English Abstract↗

PubMed2002

Influence of UV radiation and nitrosamines on the induction of mycotoxins synthesis by nontoxigenic moulds isolated from feed samples.

The effects of UV radiation and nitrosamines on the induction of mycotoxin biosynthesis by some nontoxigenic moulds isolated from feed samples collected from Egypt and Poland was investigated. Nontoxigenic strains of Aspergillus flavus P-63, A. niger EN-200 and A. ochraceus P-157 synthesized mycotoxins (aflatoxins and ochratoxin, A) after exposure to near UV radiation for 120-210 min. Nitrosamines (DMNA and DENA) at 30 up to 1000 ppm induced the synthesis of aflatoxins by nontoxigenic species of A. flavus ES-255 and P-63 and A. niger EN 200. Near-UV radiation and nitrosamines had no influence on the induction of mycotoxin synthesis by Penicillium and Fusarium isolates. All nontoxigenic strains of Aspergilli which synthesized aflatoxins in the presence of 1000 ppm nitrosamines, also synthesized continuously aflatoxins during the next fifteen generations. Near-UV radiation and nitrosamines had a mutagenic effect on the induction of mycotoxins synthesis by nontoxigenic moulds.

Aspergillus↗

PubMed1995

IARC activities in mycotoxin research.

The creation of the International Agency for Research on Cancer (IARC) in May 1965 occurred only two years after publication of the chemical structure of the aflatoxins, and the investigation of a possible link between exposure to these compounds and liver cancer incidence was initiated by IARC as early as 1968. Thus, mycotoxins were one of the first topics of research at IARC and the Agency's special interest in cancer in developing countries has contributed to a sustained effort in this research field. The work performed comprises a number of aspects including laboratory research into mechanisms of action and methods for destruction of mycotoxins, epidemiological studies, and through evaluation of the carcinogenic potency of these toxins in the "IARC Monographs on the Evaluation of the Carcinogenic Risks to Humans." A particular feature has been the integration into epidemiological studies of biomarkers of mycotoxin exposure (e.g., to aflatoxin, ochratoxin A) developed in the IARC laboratories. The above research areas are described briefly below and future activities are discussed in relation to present knowledge and the possibilities of achieving primary prevention of cancer. Another field of activity in which IARC has been strongly involved is that of quality assurance with the organisation of the mycotoxin check sample programme [Friesen, 1989: J Toxicol-Toxin Reviews 8:363-373]. This activity will, however, not be discussed in this article in view of space limitations.

Aflatoxins↗

PubMed1998

Molecular phylogenetic, morphological, and mycotoxin data support reidentification of the Quorn mycoprotein fungus as Fusarium venenatum.

Molecular phylogenetic, morphological, and mycotoxin data were obtained in order to investigate the relationships and identity of the Quorn mycoprotein fungus within Fusarium and to examine Quorn strains and commercial Quorn food products for trichothecene mycotoxins. Phylogenetic analyses of aligned DNA sequences obtained via the polymerase chain reaction from the nuclear 28S ribosomal DNA, nuclear ribosomal internal transcribed spacer region, and beta-tubulin gene exons and introns indicate that the Quorn fungus is Fusarium venenatum, rather than F. graminearum as previously reported. All of the Quorn strains examined were morphologically degenerate aconidial colonial mutants except for NRRL 25139, which produced chlamydospores in recurved terminal chains together with mostly 5-septate sporodochial conidia on doliform monophialides diagnostic of F. venenatum. Bootstrap and decay analyses provide strong support for a monophyletic lineage containing F. venenatum and several other type A trichothecene-producing species, while reference strains of F. graminearum were nested in a separate clade of species that produce type B trichothecenes and/or zearalenone. Analysis of mycotoxins from rice cultures inoculated with Quorn strain NRRL 25416 revealed that four type A trichothecenes are produced, but at low levels relative to strain NRRL 22198 of F. venenatum. No trichothecene mycotoxins, however, were detected from the analysis of three commercial Quorn products marketed for human consumption in England.

DNA, Fungal↗

PubMed1998

Effects of tamoxifen, melatonin, coenzyme Q10, and L-carnitine supplementation on bacterial growth in the presence of mycotoxins.

The involvement of toxic oxygen intermediates in the bacteriostatic effects of mycotoxins (T-2 toxin, deoxynivalenol, ochratoxin A, aflatoxin B1, and fumonisin B1) was investigated by producing bacterial growth curves using turbidimetry assays in the presence and absence of oxygen radical-scavenging substances. The strains used in this study included Escherichia coli (FT 101), Streptococcus agalactiae (FT 311, FT 313, FT 315), Staphylococcus aureus (FT 192), Yersinia enterocolitica (FT 430), Salmonella infantis (FT 431), Erysipelothrix rhusiopathiae (FT 432), Lactobacillus plantarum (FT234) and Lactobacillus casei (FT 232). Tamoxifen, melatonin, l-carnitine and coenzyme Q10 were used as radical scavengers against oxygen toxicity to the strains studied. Tamoxifen was the most effective in inhibiting bacterial growth when used at a high concentration, whereas melatonin and l-carnitine were less effective. A combination of l-carnitine and coenzyme Q10 provided better protection against oxygen toxicity caused by the mycotoxins growth than they did individually. It was concluded that oxygen radicals are involved in the killing of bacteria and that there is endogenous formation of toxic oxygen products by mycotoxins. The objective of this study was to determine whether the antioxidants were able to counteract the toxic effects of the mycotoxins. The data obtained indicate that bacterial growth can be inhibited especially by T-2 toxin, aflatoxin B1 and ochratoxin A and that this effect can be partially counteracted by antioxidants such as coenzyme Q10 plus l-carnitine.

Aflatoxin B1↗

PubMed2001

The mycotoxin ochratoxin A alters intestinal barrier and absorption functions but has no effect on chloride secretion.

Ochratoxin A (OTA) is a mycotoxin that contaminates cereals and animal feed and causes nephropathy to a variety of animal species. OTA is also known as a potent immunotoxic, teratogenic, and carcinogenic mycotoxin. In addition, OTA ingestion induces intestinal injuries, including inflammation and diarrhea. With the aim to study the cellular mechanisms associated with the intestinal toxicity of OTA, two human epithelial intestinal cell lines (HT-29-D4 and Caco-2-14 cells), widely used as in vitro models for the intestinal epithelium, were incubated with OTA. The main effects of the mycotoxin were an inhibition of cellular growth and a dramatic decrease of transepithelial resistance in both cell lines. Since transepithelial resistance reflects the organization of tight junctions over the cell monolayer, these data may suggest that OTA could potentiate its own absorption through paracellular pathways. OTA induced a 60% decrease of sodium-dependent glucose absorption but increased the absorption of fructose and L-serine in HT-29-D4 cells. Moreover, the mycotoxin did not inhibit the cAMP-dependent chloride secretion through the cystic fibrosis transmembrane conductance regulator channel. The inhibitory effect of OTA on active glucose transport was partially antagonized by L-phenylalanine, but not by alpha-tocopherol, suggesting that the toxicity of OTA could result from an inhibition of protein synthesis, rather than an induction of lipid peroxidation. In particular, OTA affected the protein content of plasma membrane microdomains, which are known to regulate tight junction assembly and intestinal transport activity. Taken together, these data showed that OTA alters both barrier and absorption functions of the intestinal epithelium.

Caco-2 Cells↗

PubMed1999

Effect of processing on Fusarium mycotoxins.

Mycotoxins are secondary metabolites produced by a wide variety of fungal species that contaminate food or feed. Fumonisins (FUM), deoxynivalenol (DON) and zearalenone (ZEN) are examples of common mycotoxins in grains that have been shown to affect human and/or animal health. Physical, chemical and biological methods have been used for decontaminating grains containing these toxins. Some treatments reduce the concentration of mycotoxins while others are ineffective. For example, removal of damaged grain by density segregation can reduce DON and ZEN concentrations in corn and wheat. In contrast, thermal processing is usually ineffective for reducing the FUM and ZEN content of foods. More work is needed to identify effective methods for detoxifying mycotoxin contaminated food.

Animals↗

PubMed1986

Biological reactive intermediates of mycotoxins.

The various reactions involved in the formation and actions of biological reactive intermediates of AFB1 are undoubtedly common to the wide variety of mycotoxins. The structural diversity of mycotoxins and their widespread occurrence in nature has made them a significant class of model environmental toxicants for mode of action studies. Identification of the reactive intermediates of prototype mycotoxins and elucidation of their reactions with molecular receptors will provide information useful for the design of antidotes of other remedial measures and for a better understanding of the mechanisms of action of comparable environmental toxicants. This type of studies will also permit the more precise biochemical analyses to be applied to the assessment of health risk due to exposure to mycotoxins.

Aflatoxin B1↗

PubMedDate not supplied

High-performance liquid chromatographic screening method for mycotoxins using new retention indexes and diode array detection.

A reversed-phase high-performance liquid chromatographic (RP-HPLC) screening method for the determination of mycotoxins has been developed. The toxins were characterized by retention indexes and on-line UV spectra produced with a diode array detector (DAD). Retention indexes of mycotoxins exhibiting a wide range of polarities and chemical structures were determined during linear gradient elution with an acetonitrile/water solvent system. The retention index scale was based on the use of a new homologous series of 1-[4-(2,3-dihydroxypropoxy)phenyl]-1-alkanones (D-compounds) as internal standards. The mycotoxins studied were: five trichothecenes of group A: T-2 toxin (T-2), HT-2 toxin (HT-2), diacetoxyscirpenol (DAS), neosolaniol (NEO), and an isomer of neosolaniol (NEO isomer); three trichothecenes of group B: nivalenol (NIV), deoxynivalenol (DON), and fusarenon-X (FUS-X); four aflatoxins: B1, B2, G1, and G2; and five other mycotoxins: sterigmatocystin (STE), zearalenone (ZEA), ochratoxin A (OCH A), citrinin (CIT), and patulin (PAT).

Chemical Phenomena↗