Knowledge Center Catalog

Contamination by micromycetes and mycotoxins of dry maize grain and flour in Armenia

Griroryan, K.

Contamination by micromycetes and mycotoxins of dry maize grain and flour in Armenia - Tbilisi (Georgia) CIMMYT : 2004 - p. 370-371 - Printed

Abstract only

A review of scientific literature and the accumulated experience in phytopathologic and mycotoxicological analysis of stored dry maize grain enable to characterize this product as a favorable medium for developing mold fungi and mycotoxins produced thereby being dangerous to the human and animal health. .Geography of grain mycocontaminants is wide like the geography of cultivated maize. However, the composition of specific mycobiota and its toxicity degree at specific and strain levels depend on the combination of many factors, which dictates the necessity for regional researches. Since 1997, the monitoring of contamination by micromycetes of locally produced maize and of the imported one has been conducted in Armenia. 36 species and varieties of contaminating fungi from two classes have been revealed by a toxocological analysis. From class Zygomycetes only species Rhizopus nigricans is found. The remaining 35 species refer to mitospore fungi from class Hyphomycetes. Their development is noted shortly after harvesting on maizecobs in the form of an abundant mold patch, frequently assuming a mosaic tinge, which is conditioned by the development of fungal complex of different generic and specific origin. Molding is not always visible in the grain mass, especially in flour, although check- ups for sporulation showhigh incidence of propagules 10x10SKOE/g. Systematically, the revealed fungi are of seven genera: Rhizopus (1 species), Penicillium (13), Aspergillus (9), Fuzarium (8), Cladosporium (1), Alternaria (2), and Stemphylium ( 1 ). Maize from Russia and Italy was mainly affected by species of Fuzarium. Maize from the USA was affected by Fuzarium, as well as by Aspergillus flavus, A. terreus and A. niger. Maize meal from Italy had spores at the rate of 5x10 2 fungi F. moniliforme and the from Georgia, bought on the market, in a week became completely molded by species F. moniliforme, A. japonicum and p granulatum. It should be noted that some fungal species have regional association within Armenia as well. Thus in the Ararat region grain, the characteristic contaminants are Penicillium viridicatum, A ochraceus- well-known producers of ochratoxin A. In the samples from Echmiadzin region species A. jlavus, A. fumigatus and F. moniliforme are often found. In Idjevan region predominate Cladosporium herbarum, and in Sevan region -p crustorum, p. oxalicum, p. hordei, A. ochraceus. Also common and dominating for Armenia are species Fuzarium, particularly polytoxic F moniliforme, F culmorum. In this connection, the above- mentioned species are to be given special attention as producers of mycotoxins zearalinon, moniliformin, DON; etc. Biotesting of an aggregated extract of samples of maize seeds from Armenia with strongly affected by species F. moniliforme and F. culmorum revealed high degree of toxicity. Nearly in all the samples there was found zearalinon at the rate of up to 8 mg/kg. Chromatographical analysis of all the samples showed the absence of DON. Moniliformine was found in four samples out of the 11 tested. The conducted studies of the specific composition of contaminating fungi of dry maize and their toxin-forming ability evidence the urgency of this problem for Armenia.


English


Alternaria
Armenia
Aspergillus flavus
Cladosporium
Fungi disease
Fusarium
Maize
Mycotoxins
Penicillium
Plant pathology
Stemphylium
Toxicology

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