Paul Vincelli
University of Kentucky Extension Plant Pathologist
Aflatoxins are
potent, naturally occurring toxins that sometimes develop in corn and certain
other crops. Aflatoxins are also among
the most carcinogenic substances known.
There are well-defined limits on how much aflatoxin is allowable in
corn, based on the intended end use. For
example, corn intended for human consumption must have less than 20 ppb
(parts-per-billion!). More information
on aflatoxin can be found in the UK Extension publication, Aflatoxins in Corn, ID-59, at http://bulletin.ipm.illinois.edu/article.php?id=1244.
The
prevalence of drought conditions this growing season may result in aflatoxin
contamination, at least sporadically. Some
agents have expressed interest in informally scouting for the problem in
advance of harvest. This is an excellent
idea. The problem is, it is very
difficult to assess standing corn crops for aflatoxin contamination. Some of the reasons for this include:
·
The
mold associated with aflatoxin may not always be visible in contaminated grain.
·
The
presence of the mold does not mean aflatoxin is present.
·
There
are several green molds on corn, and they can be hard to tell apart.
·
Even
when it occurs, aflatoxin is contamination is very sporadic for lots of reasons,
so a grower may have very high levels in one field and low levels in another.
Having now
lowered expectations, I do think scouting is a good idea, especially this
year. It might help producers manage
their risks a little more wisely.
