SEARCH · PubMed Health

Results for “Mycotoxin”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources

PubMedDate not supplied

Mycotoxin methodology.

The development of methods with high specificity and low limits of determination, as well as screening methods that are convenient for detection and rough quantitation of mycotoxins, has proceeded at an accelerating rate over the past few years. Of particular interest has been the widespread application of high performance liquid chromatographic and immunoassay techniques in mycotoxin methodology. An overview of the latest developments in mycotoxin methodology is presented with emphasis on the need for attention to sampling and sample preparation, the basic principles supporting the analytical methodology, the need for techniques to confirm analyte identification, and the requirement for high-quality reference materials.

Aflatoxins↗

PubMedDate not supplied

Criteria for determining purity of Fusarium mycotoxins.

Physical and chemical properties that may be used to determine the purity of several Fusarium mycotoxins have been investigated. A combination of analytical procedures, which include high performance thin-layer chromatography (HPTLC), liquid chromatography (LC), gas chromatography (GC), gas chromatography/mass spectrometry (GC/MS), ultraviolet spectrometry (UV), and nuclear magnetic resonance (NMR) spectrometry have been used to examine mycotoxin standards obtained from commercial sources and from laboratory fermentations. Results of this investigation indicate that commercially available standards are greater than 90% pure, but the label weight of purchased reference standards in individual containers should be verified. Mycotoxin standards, determined to be greater than 98% pure by HPTLC, LC, and GC/MS, were examined by UV spectrometry and the coefficients of extinction were determined. An interlaboratory study, involving 5 collaborators who determined coefficients of extinction (in methanol) for identical samples, gave the following results: alpha-zearalenol (lambda 236 = 28 538 +/- 558); beta-zearalenol (lambda 238 = 24 963 +/- 747); deoxynivalenol (lambda 219 = 6395 +/- 349, lot 1), (6020 +/- 228, lot 2); and T-2 toxin (lambda 202 = 3681 +/- 255). UV maxima and coefficients of extinction are also reported for HT-2 toxin (lambda 202 = 1959), diacetoxyscirpenol (lambda 203 = 2487), neosolaniol (lambda 203 = 2644), nivalenol (lambda 220 = 5142), and fusarenon-X (lambda 217 = 5997).

Chromatography, Gas↗

PubMedDate not supplied

Worldwide occurrence of mycotoxins in foods and feeds--an update.

In a review presented at the first FAO/WHO/UNEP Conference on Mycotoxins in 1977, the occurrence of aflatoxins, zearalenone, ochratoxin A, citrinin, trichothecenes, patulin, penicillic acid, and the ergot alkaloids was indicated to be significant in naturally contaminated foods and feeds. The information presented on aflatoxin contamination greatly exceeded that for all other mycotoxins combined. This study reviews the worldwide levels and occurrence of mycotoxins in various commodities since 1976. Comparatively few countries have lowered the acceptable levels for aflatoxins in susceptible commodities. However, intensified efforts are needed to establish control of aflatoxin levels in the global food supply, particularly in peanuts, tree nuts, corn, and animal feeds. Extensive deoxynivalenol (DON) contamination of grains, especially wheat, was demonstrated. Co-contamination of grains by Fusarium toxins, especially DON and nivalenol, with zearalenone to a lesser extent, was reported. However, more information on co-occurrence of Fusarium toxins in cereals should be developed. When contamination of feeds by ochratoxin A was significant, this toxin occurred in swine kidney and smoked meats in high levels. On the basis of occurrence and/or toxicity, patulin and penicillic acid contamination of foods does not appear to be of real concern. More recent developments suggest, however, that expanded monitoring studies of Alternaria toxins, moniliformin, citrinin, cyclopiazonic acid, penitrem A, and ergot alkaloids are indicated.

Animal Feed↗

PubMedDate not supplied

[The significance of mycotoxin assimilation for the contamination of milk and milk products].

The two possible pathways contaminating milk and milk products with mycotoxins are either the secretory or post-secretory route. The latter is of only little importance due to cooling conditions in production and storage. A secretory contamination can only occur with such mycotoxins, which undergo no complete degradation through their passage into the milk. From the mycotoxins, present in cow's feed; virtually only aflatoxin B1 yields a milkborne metabolite, the aflatoxin M1. The carry over rate is low (2 +/- 1%), but can be enhanced by polyhalogenated biphenyls, also present in the forage. Under normal conditions, however, this enhancement will not be measurable due to low equimolar concentrations of both reactants. The aflatoxin M1 content in herd's bulk milk depends exclusively on the content of the precursor aflatoxin B1 in the ration of the cow and is with less than 10 ng/kg fairly low at present in the Federal Republic of Germany. A careful supervision of the imported feed ingredients for mixed feed, however, will ensure to keep those batches out of dairy cow feeding which exceed a certain level of aflatoxin. The legal threshold is 10 micrograms/kg, being even too high to ensure a milk containing less than 10 ng/kg under high energy feeding conditions. The discussed thresholds for aflatoxin M1 in milk are 50 and 10 ng/kg resp., the latter value is scheduled for milk used in infant nutrition. To keep this low concentration the intake of aflatoxin B1 must be less than 2 micrograms/kg of the daily ration.

Animal Feed↗

PubMed1988

In vitro effect of T-2 mycotoxin on the immune response of mice.

The in vitro biologic effects of T-2 mycotoxin on the immune response of mice was undertaken. Twenty nanograms of toxin abrogated the immune response to the T-dependent antigen sheep RBC, whereas a partial response was observed when 2 ng was used. Analysis of cell culture viabilities indicated that cell death occurred with toxin doses that coincided with the diminished immune responses. A similar decreased response was observed against the T-independent antigen, TNP-lipopolysaccharide, indicating toxic effects on both B and T lymphocyte populations. Delay of toxin administration as much as 116 hours of the 120-hour incubation period still resulted in a substantially diminished immune response, indicating the toxin acts on both the afferent and efferent immune systems. Equal effects were observed for mice of the b, d, and k haplotype, indicating no apparent strain variability in sensitivity to T-2 mycotoxin effects. These results indicated that T-2 mycotoxin can modulate the immune response, and that this modulation is attributable to direct toxic effects on the cells of the immune system.

Animals↗

PubMed1986

Genotoxicity of mycotoxins.

Mycotoxins with their diversified structures have been a class of good model compounds, or a good tool, for evaluating the usefulness of short-term genotoxicity tests and for elucidating the mechanism of mutagenicity and carcinogenicity. Despite the limitations of these tests in predicting carcinogenicity, the genotoxicity of mycotoxins as shown by the results of a battery of genotoxicity tests indicates that mycotoxins are indeed a class of significant naturally occurring environmental carcinogens which warrant rigorous regulatory actions.

Aflatoxin B1↗

PubMed1979

Evaluation of brine shrimp (Artemia salina) larvae as a bioassay for mycotoxins in animal feedstuffs.

Brine shrimp larvae was tested as a possible simple biological screening system to identify specimens of animal feedstuffs that should be examined further by chemical analytical procedures for mycotoxins. All extracts of the control, nonmouldy feedstuffs increased larval mortality, this being most marked in the case of silage. Chemical and biological testing of diagnostic specimens indicated that the bioassay identified two of four chemically positive specimens and 59 of 135 chemically negative specimens and 59 identified larvicidal compounds present in normal feedstuffs gave a high percentage (56%) of false-positive bioassay results when compared to the results of chemical analyses for three mycotoxins. The use of brine shrimp larvae did not materially reduce the necessity of conducting chemical analyses for mycotoxins.

Aflatoxins↗

PubMed1977

Mutagenicity and inducibility of DNA single-strand breaks and chromosome aberrations by various mycotoxins.

Mutagenicity of various mycotoxins and the efficiency of mutagenic mycotoxins in producing DNA single-strand breaks and chromosome aberrations were examined using a mammalian cell line. It was found that aflatoxin-B1, mycophenolic acid, patulin, penicillic acid, and sterigmatocystin induced 8-azaguanine-resistant mutations. Aflatoxin-B1, mycophenolic acid, and sterigmatocystin had little effect on DNA single-strand at high concentrations. In the treatment with patulin and penicillic acid, severe breaks were found at higher concentration than at the concentration where the mutation was induced. Incidence of chromosome aberrations by the treatment with these mycotoxins correlated fairly well with their mutagenic activity. Chaetoglobosin-B, fusarenon-X, (--)luteoskyrin, and ochratoxin-A did not induce 8-azaguanine-resistant mutation.

Aflatoxins↗

PubMed1977

Some newly discovered mycotoxins.

The discovery of the aflatoxins in 1960 has taken place in the present era of the intense awareness of the importance of environmental contaminants. It has dramatically influenced subsequent fungal research with the resulting rapid increase in the number of publications describing mycological, chemical, toxicological and epidemiological aspects of mycotoxins. In this contribution results will be discussed which were published only subsequent to 1970. In this period the importance of several new classes of mycotoxins was realized, e.g. the toxic cytochalasins and the tremorgens. The potential role of highly oxygenated metabolites in mycotoxicosis was emphasized by the establishment of secalonic acids A and D. emodin, moniliformin, altenuisiol alternariol and austdiol as toxins. The structure of viridicatumtoxin, C30H31NO11, a metabolite produced by Penicillium viridicatum will be described. It is a novel compound, structurally related to the tetracyclines. The characterization of several mycotoxins from other toxigenic fungi will be reported.

Cytochalasins↗

PubMed1984

Leucinostatins, peptide mycotoxins produced by Paecilomyces lilacinus and their possible roles in fungal infection.

Peptide mycotoxins "leucinostatins" were obtained from the culture strains of Paecilomyces lilacinus, which were isolated both from soil and a case of human oculomycosis. Comparative studies of the symptoms of experimental keratomycosis caused both by the inoculation of P. lilacinus and by direct administration of leucinostatins into the infection model in rabbit suggested the possible role of leucinostatins in the inflammatory response of invaded tissues. Leucinostatin was formerly reported as a single entity. However, in the course of the structural studies, leucinostatin was found to be a complex of two closely related components, and the structures of the both mycotoxins were determined. Both of the mycotoxins possessed high toxicity to experimental animals. The intraperitoneal and oral LD50 values in mice were 1.8 and 5.4 to 6.3 mg/kg by a single administration. Toxicological studies showed that leucinostatins have some potent effects on liver cells after oral administration. It was also found that leucinostatins exhibit strong uncoupling activity on rat liver mitochondrial system.

Animals↗

PubMed1983

[Mycotoxins and food contamination].

The contamination of food and feed by fungi and their toxins (mycotoxins) has to be considered as a serious hazard in the daily live. Mycotoxins are natural contaminants in foods and could induce several syndromes. Many mycotoxicosis are described. The control and surveillance of mycotoxins involve the carrying out of surveys, toxicological studies and institution of regulations.

Animals↗

PubMedDate not supplied

[Possible contamination of rice grains by mycotoxins in a temperate climate].

The authors studied formation of mycotoxins (aflatoxins B1, B2, G1, G2, ocher toxin A, sterigmatocystine, patulin, toxins T-2 and HT-2, zearalenon. penicillic and kojic acids) under the conditions of experimental storage of rice grain, which was demonstrated to be comparatively resistant to contamination with mycotoxins. Analysis of 208 samples of rice grain of normal quality did not reveal any mycotoxins. In 130 samples taken from the batches subjected to experimental self-heating, aflatoxin B1 was found in 9-10% of cases in concentrations from 16 to 330 micrograms/kg. Sixty-seven per cent of the contaminated samples contained an insignificant amount of aflatoxin B1 (less than or equal to 50 micrograms/kg). Aflatoxin G1, zearalenon, penicillic and kojic acids were discovered in individual samples. Aflatoxins B1 and G1 were accumulated in the rice grain with an initial moisture of greater than or equal to 16%. The amount of aflatoxins and Aspergillus flavus reached a maximum when the temperature of the grain mass was 35-45 degrees C. The authors demonstrated that the toxins in the bulk grain distributed uniformly and described the features of their formation in rice grain, linked with the protective role of the floral film. Provided the data on the toxigenous potential of the microscopic fungi isolated from rice grain. Indicated that during the processing of rice grain, one can see a substantial effect of decontamination, being equal to 88% upon production of rice groats and to 37% upon culinary treatment of rice. Demonstrated that hydrothermal treatment leads to the destruction of over 90% of aflatoxin B1.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxins↗

PubMed1981

The effects of naturally occurring bisdihydrofuran ring-containing mycotoxins on cultured chick embryonal hepatocytes.

The cytotoxicity of 16 naturally occurring mycotoxins which contain the bisdihydrofuran ring was evaluated by electron-microscopy and radioautography in a primary culture of chick embryonal hepatocytes. A series of nucleolar changes occurred, including the appearance of microsegregation (stage I), concentration of nucleolar structure (stage II), formation of macrosegregation, fragmentation of nucleoli, and the appearance of homogeneously granular nucleoli (stage III). These nucleolar changes correlate well with the inhibition of RNA synthesis calculated from the results of radioautography. The compounds containing a 2,3-double bond in the bisdihydrofuran ring were most toxic. However, it was clear that there was a remarkable difference between mycotoxins of angular type (group A) and those of linear type (group C). Therefore, not only the active site in the molecule but also the shape of the molecule may play an important role in the cytotoxicity of these mycotoxins.

Aflatoxins↗

PubMedDate not supplied

[Mycotoxin formation during the storage of unprocessed freshly harvested corn].

The formation of mycotoxins by microscopic fungi was studied during experimental storage of freshly harvested corn in cobs and grain at a 26--35% humidity level. During the corn storage in cobs aflatoxins, kojic acid and zearalenon and during the corn storage in grain zearalenon and ochretoxin A were detected in corn. Mycotoxins we found in maximum amounts in the areas of cob storage where the temperature reached 30--45 degrees C due to selfheating. The synthesis of mycotoxins can be arrested or they can be degraded at further temperature rise to 50--60 degrees C. The highest content of zearalenon, ochretoxin A and kojic acid was seen on the 8--12th day after the onset of self-heating.

Food Contamination↗

PubMed1980

Protocols for surveys, sampling, post-collection handling, and analysis of grain samples involved in mycotoxin problems.

This report examines and summarizes current knowledge regarding mycotoxin surveys, sampling techniques, conditions conducive to post-collection production of mycotoxins in grain samples, and analytical methods for mycotoxin analysis. Priority attention is given to samples of corn suspected of containing aflatoxin. The report includes recommendations where deems appropriate by the Ad Hoc Work Group.

Aflatoxins↗

PubMed1994

[Health risks of mycotoxins for humans].

Fungi cause diseases in humans in different ways. Due to production of secondary metabolites by molds, dematiaceous hyphomycetes, and primary plant pathogenic fungus species intoxications are included in their pathogenic potency. Mycotoxins mostly enter the body by ingestion of food because they are contaminants of plant products and in case of carry over also of animal products. Recent investigations have shown that mycotoxins detected in feed and food during microbial deterioration can also be produced inside warm-blooded organism, e. g. with aspergillosis in animals (mammals and birds). This means an enhanced risk for humans to suffer from mycotoxicosis, in which the toxic agent has an exogenic or endogenic source. Therefore, attention should be paid to the fact that mycotoxins are not only damaging cells; they very often possess a genotoxic potential.

Animals↗

PubMed1976

DNA-attacking ability of carcinogenic mycotoxins in recombination-deficient mutant cells of Bacillus subtilis.

Thirty mycotoxins and 5 chemically modified toxins were tested for DNA-attacking ability in the rec assay using the recombination-deficient mutant of Bacillus subtilis M45 (rec-) and the parent strain H17 (rec+). Six Penicillium toxins (citrinin, penicillic acid, patulin, (-)-luteoskyrin, (+)-rugulosin, and PR-toxin), 5 Aspergillus toxins (aflatoxins B1 and G1, sterigmatocystin, O-acetylsterigmatocystin, and O-acetyldihydrosterigmatocystin), and 2 Fusarium toxins (zearalenone and zearalenol-b) were positive. Among these 13 compounds, the following 8 mycotoxins have been reported to be carcinogenic in animals: citrinin, penicillic acid, patulin, (-)-luteoskyrin, (+)-rugulosin, aflatoxins B1, and G1, sterigmatocystin. Correlation between the rec effect and in vivo carcinogenicity of mycotoxins is discussed.

Aflatoxins↗

PubMedDate not supplied

[Propagation of toxigenic fungi and mycotoxins in various grains].

The frequency of occurrence and toxigenicity of various strains of Aspergillus flavus (663 stairs) and of Fusarium spp. (459 strains) isolated from grain of various crops from four grain-producing areas were studied. The analysis of mycotoxins in 1038 grain samples (wheat, rye, rice and corn) and in 58 samples of sun flower seeds collected from commercial batches showed that aflatoxins B1 and G1, deoxynivalenol, and zearalenone are the basic microbial contaminants of grain, while toxin T-2 and diacetoxyscirpenol were found much more rarely. Ochratoxin A, penicillic and kojic acids were found only in several samples. The occurrence of the mycotoxins and contamination levels depended on grain-producing areas. The risk of mycotoxins invasion in grains was greater in southern humid regions of Russia, Kazakhstan and Uzbekistan.

Aspergillus flavus↗