October 21, 2010

US researchers identify potential reproductive species for mycotoxins

Using a molecular procedure they developed, USDA Agricultural Research Service (ARS) researchers have identified more than 18 species of black aspergilli, several of which have the potential to produce mycotoxins.

Researchers also found that several A.niger species that were thought to be incapable of producing mycotoxins can produce ochratoxins - carcinogenic mycotoxins that can affect humans, livestock, and poultry.

These A. niger species were deemed as non-producers of mycotoxins based on in vitro culture media, but on corn they were indeed producers. A. niger, one of a group of black-spored fungi, is a common contaminant on corn, peanuts, several other important food and feed ingredients, and products made from them.

Fumonisins are a class of mycotoxins that are known to be carcinogenic and are primarily produced by the Fusarium species of fungi. Some of the black aspergilli identified in this study are also producers of this mycotoxin.

According to the research team, the A. niger complex of species acts within corn and peanuts as an endophyte, living within the tissues of the plant, but causing no harm to the plant itself.

Three species of A. niger are identified in US corn and peanuts as symptomless endophytes, which suggests the potential for concern as pathogens and as food safety hazards.

Black aspergilli, generally viewed as post-harvest pathogens, produce rots of grapes, corn and numerous other fruits and grain.