RESUMO
Thirty-five samples of poultry feeds and corresponding raw materials (maize, soybean and meat meal) from a processing plant were analyzed to evaluate the distribution and toxigenicity of Aspergillus section Flavi isolates. Mycological analysis of the samples indicated the presence of five fungal genera (Aspergillus, Penicillium, Fusarium, Cladosporium, and Eurotium). Aspergillus flavus was the predominant species being present in 48.5% of the analyzed samples. Ninety-one isolates belonging to Aspergillus section Flavi were isolated; ninety were identified as A. flavus and only one as A. parasiticus. Fifty-seven isolates were capable of producing sclerotia, 41 were identified as L-type strains and 16 as type S. Fifty-seven percent of the isolates produced AFB1 levels ranging from 0.05 µg/kg to 27.7 µg/kg whereas 86.8% produced CPA from 1.5 µg/kg to 137.8 µg/kg. L-strains produced from 0.05 to 14.8 µg/kg of aflatoxin and type S produced levels from 0.05 to 1.65 µg/kg. No significant differences in CPA production among S- and L-strains were observed. Sclerotial isolates produced AFB1 levels ranging between 0.05 and 27.7 µg/kg and CPA levels from 3.8 to 47.3 µg/kg. More than half of the A. flavus isolates were able to produce AFB and CPA simultaneously. Twenty percent of the 35 samples were contaminated with aflatoxin B1 whereas 34.3% were contaminated with CPA. The high rate of CPA producing isolates represents a potential risk of contamination with this toxin in poultry feeds.
Assuntos
Aflatoxinas/análise , Ração Animal/microbiologia , Aspergillus/isolamento & purificação , Contaminação de Alimentos , Ração Animal/análise , Animais , Aspergillus/classificação , Indóis/análise , Aves Domésticas , Glycine max/microbiologia , Zea mays/microbiologiaRESUMO
Each year, a significant portion of the peanuts produced cannot be marketed because of fungal disease at the postharvest stage and mycotoxin contamination. Antioxidants could be used as an alternative to fungicides to control ochratoxigenic fungi in peanuts during storage. This study was carried out to determine the effect of the antioxidant butylated hydroxyanisole (BHA) and the antimicrobial propyl paraben (PP) on the lag phase before growth, growth rate, and ochratoxin A (OTA) production by Aspergillus section Nigri strains in peanut kernels under different conditions of water activity (aw) and temperature. At 20 mM/g BHA, 18 degrees C, and 0.93 aw, complete inhibition of growth occurred. For PP, there was no growth at 20 mM/g, 18 degrees C, and 0.93, 0.95, and 0.98 aw. BHA at 20 mM/g inhibited OTA production in peanuts by Aspergillus carbonarius and Aspergillus niger aggregate strains at 0.93 aw and 18 degrees C. PP at 20 mM/g completely inhibited OTA production at 18 degrees C. The results of this work suggest that PP is more appropriate than BHA for controlling growth and OTA production by Aspergillus section Nigri species in peanut kernels.
Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Arachis/microbiologia , Aspergillus niger , Contaminação de Alimentos/prevenção & controle , Ocratoxinas/biossíntese , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/crescimento & desenvolvimento , Aspergillus niger/metabolismo , Hidroxianisol Butilado/farmacologia , Hidroxitolueno Butilado/farmacologia , Contagem de Colônia Microbiana , Relação Dose-Resposta a Droga , Manipulação de Alimentos , Conservação de Alimentos/métodos , Humanos , Parabenos/farmacologia , TemperaturaRESUMO
AIM: To determine fungal genera, Aspergillus and Fusarium species and aflatoxin B(1) (AFB(1)), zearalenone (ZEA), deoxynivalenol (DON), fumonisin B(1) (FB(1)) contamination from pre- and postfermented corn silage produced in the most important region of Argentina where silage practice is developed. METHODS AND RESULTS: Sampling of corn silos was performed manually through silos in transects at three levels: upper, middle and low sections. AFB(1) and FB(1) were quantified by high-performance liquid chromatography, zearalenone by enzyme-linked immunosorbent assay and DON by gas chromatography. Over 90% of the samples showed counts higher than 1 x 10(4) CFU g(-1). Aspergillus flavus and Fusarium verticillioides were the prevalent species. Some tested samples were contaminated with AFB(1), ZEA, DON and FB(1). CONCLUSIONS: This study demonstrates the presence of fungi and AFB(1), ZEA, DON and FB(1) contamination in corn silage in Argentina. SIGNIFICANCE AND IMPACT OF THE STUDY: This manuscript makes a contribution to the knowledge of mycotoxins in Argentinean silage in particular because the environmental conditions in this country differ from those of most reports. The comparison of pre- and postfermentation silage is also outstanding. Therefore, information on fungi and mycotoxins present in silage--an increasingly popular commodity--is useful to estimate potential risk for animal and human health.