BY KARIN OLAFSON
“Mycotoxins are robust and
they can survive many of the
processes that would destroy other
contaminants.”
–Maria DeRosa
Down the line, if mycotoxins were to
go undetected, they could also become a
health issue for the consumer. Cooking
contaminated grains isn’t enough to pro-
tect the consumer from harmful effects.
“Mycotoxins are robust and they can
survive many of the processes that would
destroy other contaminants,” DeRosa ex-
plained. Depending on factors such as the
type of mycotoxin and the concentration
level, mycotoxin exposure can damage the
nervous system.
Ingesting mycotoxins can also impact
animals’ health. Blakley explained that
depending on the mycotoxin and its con-
centration, effects on animals include feed
refusal (which comes with its own range
of problematic consequences), negative
impacts on the animals’ immune system
and even abortion. “Mycotoxins are the
biggest nutritional problem we’ve seen in
livestock in the last two to three years,”
Blakley said.
CURRENT DETECTION METHODS
According to DeRosa, there are a few
different detection tests available. How-
ever, they range in cost, reliability and
duration.
“If farmers want to spend a little bit
more money and they have a little bit
more time to do the detection, then
grains can be sampled and sent to labs,”
DeRosa said. But lab tests use expensive
equipment and require the expertise of
scientists; they’re not tests everyone can
conduct or afford.
DEVELOPING THE PAPER TEST
DeRosa is working on developing a
detection test that is cheaper, faster and
more reliable than any other mycotoxin
detection test available. This new test in-
volves building aptamers—single-stranded
molecules that are similar to DNA with
binding sites that are specific to the fusari-
um mycotoxin. That is, the aptamer (also
called a DON aptamer, as it’s specific to
the DON mycotoxin) and the mycotoxin
will fit together perfectly, much like two
puzzle pieces.
The initial phase of the process was
discovering the piece of DNA that is the
ideal shape to interact with the my-
cotoxin. Once the DNA sequence was
identified, more strands could be created
synthetically based on that discovered
DNA sequence. DeRosa and her team
have been building aptamers synthetical-
ly since 2010.
“The aptamer is the main building
block that makes our sensor able to detect
the mycotoxin, rather than something
else,” DeRosa said. “The aptamer’s job is
to recognize that the toxin is present in
the sample. Without the aptamer, there’s
no sensor.”
But the aptamer on its own isn’t enough
to act as a detection model. In DeRosa’s
test, when mycotoxins are present in
the grain, the affected grain will glow.
According to DeRosa, this “takes some
chemistry”; the aptamer won’t glow when
it binds to mycotoxins unless there’s some
modification.
“The test involves fluorescent nanopar-
ticles that, when they’re locked up togeth-
er with the aptamer, there is no glow,”
DeRosa said. “When the aptamer lets go
of the nanoparticles to grab the target [the
mycotoxins], the light turns on.”
In a nutshell, the only way the test will
glow is if mycotoxins are present. Because
the aptamers are specifically shaped to
hold mycotoxins, the aptamer would rath-
er bind to the toxin than the nanoparticle,
creating the glow.
The components of the test are simple
and affordable compared to other tests. The
user collects samples on filter paper and
then illuminates them with a UV light.
“We are imagining the test being a little
kit with a UV pen and a bunch of filter
papers,” DeRosa said. It’s designed to be
easy for anyone to use—no scientific back-
ground is needed—and users will receive
an immediate answer as to whether grain
is contaminated. And because the test
is designed to be more affordable than
others out there, farmers can take more
samples and will get a better understand-
ing of contamination levels.
NEXT STEPS
According to DeRosa, the goal is to ensure
that the test is cheap enough that it can be
put into the hands of farmers and millers.
It also needs to be easy to use so they can
quickly test for mycotoxins themselves
and make a decision based on those
results. However, it also has to be robust,
stable and reliable.
Right now, the paper test is still in its
infancy and not commercially available.
Dozens of prototypes have been made
in the lab, but DeRosa wants to make
thousands and send them into the field to
be tested. “The next step is to put them in
the hands of farmers and see how it works
for them,” she said.
DeRosa also has plans to collaborate
with Art Schaafsma, a professor of plant
protection in the department of plant
agriculture at the University of Guelph
Ridgetown Campus. Schaafsma and his
team test samples for mycotoxins. This
year, Schaafsma has begun investigating
whether mycotoxins can be detected by
sampling grain dust.
“We are developing the relationship
between what’s in the dust and the grain,”
Schaafsma said. “And as DeRosa develops
the paper test further, the goal is that she
will verify her test’s effectiveness with our
samples.”
DeRosa estimates that, depending on
funding and partnerships, it might take
three to five years to determine whether
it’s feasible for this test to be used in the
field.
Spring
2016
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