Ochratoxin Production by the Aspergillus ochraceus Group and Aspergillus alliaceus

Abstract

Ochratoxin A is a toxic and carcinogenic fungal secondary metabolite; its presence in foods is increasingly regulated. Various fungi are known to produce ochratoxins, but it is not known which species produce ochratoxins consistently and which species cause ochratoxin contamination of various crops. We isolated fungi in the Aspergillus ochraceus group (section Circumdati) and Aspergillus alliaceus from tree nut orchards, nuts, and figs in California. A total of 72 isolates were grown in potato dextrose broth and yeast extract-sucrose broth for 10 days at 30°C and tested for production of ochratoxin A in vitro by high-pressure liquid chromatography. Among isolates from California figs, tree nuts, and orchards, A. ochraceus and Aspergillus melleus were the most common species. No field isolates of A. ochraceus or A. melleus produced ochratoxin A above the level of detection (0.01 g/ml). All A. alliaceus isolates produced ochratoxin A, up to 30 g/ml. We examined 50,000 figs for fungal infections and measured ochratoxin content in figs with visible fungal colonies. Pooled figs infected with A. alliaceus contained ochratoxin A, figs infected with the A. ochraceus group had little or none, and figs infected with Penicillium had none. These results suggest that the little-known species A. alliaceus is an important ochratoxin-producing fungus in California and that it may be responsible for the ochratoxin contamination occasionally observed in figs.

Colonization of wounded peanut seeds by soil fungi: selectivity for species fromAspergillussectionFlavi

“…Another species, A. alliaceus (teleomorph ϭ Petromyces alliaceus), has been transferred to section Flavi based on molecular characters (Peterson 2000). None of these other species forms aflatoxins, although A. tamarii produces cyclopiazonic acid (Horn et al 1996) and A. alliaceus produces ochratoxin A (Bayman et al 2002a).…”

Aspergillus flavus: human pathogen, allergen and mycotoxin producer

“…), and are considered to be responsible for ochratoxin A contamination of figs (Bayman et al, 2002).…”

Obtenção de mutantes de Aspergillus carbonarius via transformação genética mediada por Agrobacterium tumefaciens

“…Em uma grande variedade de produtos agrícolas em várias regiões geográficas do mundo já foi detectada a ocratoxina A (URBANO et al, 2001). Muitos destes alimentos são grãos, como cevada, milho, centeio, trigo e aveia (JORGENSEN; JACOBSEN, 2002), além de estar presente em outros produtos incluindo café, especiarias, nozes, azeitonas, uvas, e figos (BATTILANI et al, 2003;BATISTA et al, 2003;BAYMAN et al, 2002;JORGENSEN, 1998). A ocratoxina sobrevive a processamentos e pode ser encontrada em pães (SCUDAMORE; BANKS; MCDONALD, 2003), café bebida (PITTET, et al, 1996), vinhos (CABAÑES et al, 2002NAICKER, 2002).…”