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Angling
Indiana: Almost everything you'd want to know about fish safety and
fishing in Indiana
As this ScienCentral video reports, food safety experts at Purdue University
say a new technique can make screening fish for contaminants much faster.
Safety First
We’ve all heard that eating fish is healthy. That is, if that fish isn’t
contaminated.
“The consumer - especially a woman in her childbearing years -
needs to be discerning,” explains Charles
Santerre, associate professor of food and nutrition at Purdue
University specializing in chemical contaminants in food. “A woman
should carefully choose the fish she eats today to protect her baby tomorrow.”
Santerre and his team study fish in order to find out more about typical fish
contaminants, such as PCBs, or polychlorinated
biphenyls. PCBs and methylmercury,
a form of mercury found in fish, are particularly harmful to infants and young
children. This is true whether they eat the fish themselves, or get a dose from
their mothers during pregnancy or nursing. “It takes six years to rid
the body of PCBs,” explains Santerre, “and one year for mercury.”
Methylmercury, if eaten regularly, can harm the developing nervous system of
a fetus or infant. PCBs have also been linked to low birth weight and decreased
IQ.
Santerre’s goal is to help determine whether fish is contaminated. “We
want to improve the information that’s collected by the state health departments,
so that they better know what contaminants are in foods.” Santerre and
his co-workers helped develop a faster and cheaper way of detecting tainted
fish. They take a small piece of fish and grind it up. Then they run a liquid,
called a solvent, through the ground up fish that pulls the PCBs out of it.
Then they mix the PCBs with antibodies, proteins that help fight infections
and that are produced by certain cells in the immune system. The antibodies
in this particular test are special, because they bind to PCBs and they have
tiny magnetic particles attached. By placing a magnet next to the tube containing
the antibody-PCB mixture, the researchers can “hold” the antibodies
and PCBs in the tube while they pour everything else out of the tube. Lastly,
they add a few chemicals that indicate the amount of PCBs in the sample by changing
color. If there’s a lot of PCB in the fish sample, the researchers can
deduce that fish of that species from that body of water are not healthy to
eat.
“Up until recently,” Santerre says, “if you sent one sample
of fish into a laboratory, it would cost between $200 and $500 and it would
take weeks to analyze the sample. This rapid assay allows us to analyze these
in an afternoon for maybe $25 to $40 per assay - per test. So by developing
this, we’ve been able to improve the data that states collect so they
can build their fish consumption advisories and protect women.”
Try Salmon
Santerre suggests that pregnant women, nursing mothers, and young children
avoid certain fish, including swordfish, shark, king mackerel, and tilefish,
because these fish can contain high levels of mercury. Instead, he recommends
salmon, because it’s low in contaminants. “Salmon is an ideal source
for omega-3 fatty acids, which are necessary for brain development in babies
and cardiovascular health in adults.”
Santerre also says that pregnant and nursing mothers can eat other fish, such
as tuna, but in limited quantities, and that canned tuna tends to be safer than
tuna steak.
Most of all, he wants people to continue to eat fish. “That’s
the number one point in any presentation we deliver - fish is important
nutritionally, so it’s important that people eat fish.”
Santerre’s research was published in the Journal of Food Science. It
was funded by the Illinois-Indiana
Sea Grant Program, Purdue
University Research Foundation, the USDA
Agricultural Research Service and the USDA
Cooperative State Research, Education, and Extension Service.