engleski

Production of cyclopiazonic acid by aflatoxigenic and non-aflatoxigenic strains of Aspergillus flavus

Cyclopiazonic acid (CPA) is a toxic indole tetramic acid which was first isolated from culture of Penicillium cyclopium in 1968 and subsequently found to be produced by variious species both Penicillium and Aspergillus. We detected the production of CPA by several A. flavus isolates and then decided to survey whether the aflatoxigenic strains of A. flavus are the CPA producers. 76 A. flavus isolates from variety of sucrose were grown on solution medium yeast extracts sucrose (YES) broth and on malt extract agar (MEA) incubated to two weeks at 25 C. thereafter the medium was extracted with chloroform, and the chloroform extract checked by TLC procedure for the presence of CPA and aflatoxins. A control isolates (NRRL 3251) of A. flavus known to produce CPA and aflatoxins was also cultured. A msjor portion of the strains were isolated from samples of stored grains and cured smoke meat products where the incidence of A. flavus was 15-17%. Of the 76 A. vlavus isolates analysed 9 (11.8%) were found to produce aflatoxins (0.01-0.40 ug/mL) under the culture conditions utilized. This relatively low proportion of AF producers indicates a lower frequency of ability of A: flavus to produce this mycotoxin, much lower than those reported in literature. Three out of these 76 A. flavus isolates (3.9%) produced CPA only (0.5-30 ug/g), and it is noteworthy that CPA producing ability did not correlate with aflatoxin-producing ability. We had no isolates that produced both mycotoxins, whereas 9 isolates produced aflatoxin only, and 3 isolates produced CPA alone. Finally, it is important to note that production of CPA and possibility of multiple mycotoxin contamination with aflatoxin/CPA-producing isolates of A. flavus are low in our survey.

Aspergillus flavus; cyclopiazonic acid; aflatoxins

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