2012
LOGA
N COUNTY FARM OUTLOOK MAGAZINE. LINCOLN DAILY NEWS.com October 23, 2012
8
elevator starts with a 5-pound sampling
with a probe that is inserted in a random
place in the load of grain and vacuumed
up at a random depth in the load. Part of
this sampling is placed in a screening
tray and examined for quality, deformity,
discoloration and trash. Part of the sampling
is put in a device to measure moisture. And
part of the sampling is ground up and made
ready for aflatoxin testing.
A number of years ago
the aflatoxin test consisted
of shining a black light
on the sampling. An acid
present in aflatoxin glowed
under the black light and
indicated the presence
of aflatoxin. These were
commonly called “shiners,”
according to Ralph Shew
at Chestervale. More
recent research has shown that sometimes
aflatoxin may be present despite the lack of
glowing kernels, and thereforemore precise
measurement processes were needed.
The modern aflatoxin test consists of
mixing the ground sample with a methanol
solution and put into an incubator for 3
minutes. Then a reactive strip similar to a
litmus strip is inserted into the incubated
sample, and then into a digital reader to
obtain the quantitative results. This test
is now used with every corn and bean
sampling.
Corn that has large quantities of aflatoxin
present can be used to produce ethanol.
The aflatoxin is not passed on to the
ethanol product. However, in most ethanol
operations, thegrainbyproductsaremodified
and manufactured as high-protein animal
feeds. Care must be taken that the aflatoxin
is not passed on to the manufactured feed.
The USDA has set specific levels for the
presence of aflatoxin in animal feeds:
• 20
ppb is the accepted
limit for aflatoxin in grains
destined
for
human
consumption,
or
for
consumption by immature
animals, or when the
destination is not known.
• 100
ppb is the accepted
limit for aflatoxin in grains
destined for breeding cattle,
breeding swine and mature
livestock
• 200
ppb is the accepted limit for aflatoxin
in grains destined for finishing swine of
100
pounds or more.
• 300
ppb is the accepted limit for aflatoxin
in grains destined for finishing beef cattle.
Aflatoxin present in the 100-300 ppb range
in dog foods has been known to cause liver
failure in dogs if fed over an extended period.
The dog may or may not recover if put back
on a diet with low aflatoxin levels. Livestock
producers have reported that exposure to
aflatoxin in feeds can cause a larger than