Zearalenone: incidence, toxigenic fungi and chemical decontamination in Egyptian cereals.

An investigation was made for the occurrence of Zearalenone (ZEN) and Zearalenone producing fungi in cereals (corn, 50 samples; rice, 45 samples; wheat, 40 samples) collected from Egypt. ZEN was detected in 15 of 50 corn samples with an average concentration of 22.3 ppb. The incidence of ZEN in rice samples was 8.9% (4 samples of 45), and the average was 15.5 ppb. Out of 40 wheat samples 5 samples were contaminated with ZEN (12.5%) with an average of 8.8 ppb. Seventy-nine Fusarium strains belonging to 9 different species were isolated from Egyptian cereals, and when tested for ZEN production only 26 isolates were Zearalenone producer. Efficiency of H2O2 for destruction of ZEN in contaminated corn was studied at different concentration (3, 5 and 10%). The results revealed that per cent of disappearance of ZEN was found to be dependent upon the concentration of H2O2, temperature and period of exposure. The highest per cent of degradation was 83.9%, with 10% H2O2 at 80 degrees C for 16 h, followed by 75% at the same conditions for 8 h, while the lowest one obtained by 3% H2O2 at 50 degrees C for 2 h.

Mutagenic potentials of fumonisin contaminated corn following ammonia decontamination procedure.

Naturally contaminated corn implicated in an outbreak of equine leukoencephalomalacia (ELEM) in southeastern Arizona was analyzed for mutagenic potential using the Salmonella/microsome mutagenicity assay before and after treatment with the ammonia procedure. Crude acetonitrile: water (1 + 1) extracts of high-pressure/ambient temperature (HP/AT) ammonia decontaminated, HP/AT plus low pressure/high temperature (LP/HT), and non-ammoniated fumonisin contaminated corn were tested for mutagenic potentials. Relatively pure (approx. 90%) fumonisin B1 standard was also tested for comparison purposes. The results of this experiment indicate that there was no mutagenic potential for the fumonisin B1 standard at the concentrations tested (100 micrograms/plate). Also, neither the naturally-contaminated corn nor the ammonia decontaminated samples elicited a positive mutagenic response. Fumonisin B1 levels, as determined by HPLC methods, were reduced by an average of 79% via the ammonia decontamination process. It is encouraging to note that, while further work is necessary to increase the efficacy of the ammonia process to reduce fumonisin levels, the ammonia process did reduce fumonisin levels and no mutagenic potentials were apparent in the treated corn.

Genotoxic evaluation for the estrogenic mycotoxin zearalenone.

Genotoxic effects of the mycotoxin Zearalenone (ZEN) were evaluated on albino mice. The investigation was assessed using 4 criteria: chromosome aberrations in bone marrow and spermatocytes of adult male mice; chromosome analysis and teratological effects of mice embryos. Zearalenone was administrated to both adult males and pregnant females with 2 doses level (5 microg x kg(-1) and 10 microg x kg(-1) ZEN). Zearalenone was found to reduce the mitotic activity in treated males and the embryos proving that it is a cytotoxic substance. In treated males and females, it induced some chromosome abnormalities with no significant increase over the control at the doses investigated, except for some few figures. Similar results were observed for the teratological study. The results in general could consider zearalenone as a toxic mycotoxin for both adult animals and embryos. It is highly recommended that a great attention should be paid towards the toxicity of zearalenone to mono-gastric animals and human, especially it contaminate corn that is widely used in human and animal feeding.