Lox Can Be Toxic for Food Allergic
Milk protein in packaging can set off reactions
By Adam Marcus
HealthSCOUT Reporter
THURSDAY, Dec. 16 (HealthSCOUT) -- It sounds like a fish tale, but
researchers report that a protein used to prettify packaged lox can trigger
severe food allergies in some patients.
The protein, casein, is a common additive in packaged meat and fish because
of its knack for keeping these fleshy foods firm and well-textured. The
compound works by boosting the ability of another enzyme, transglutaminase,
to bind muscle proteins together.
In the Dec. 18/25 issue of The Lancet, Stef Koppelman, of the TNO Nutrition
and Food Research Institute in Zeist, the Netherlands, and his colleagues
say a 30-year-old woman had a severe allergic reaction after eating a piece
of bread topped with prepackaged smoked salmon.
Within an hour after eating one slice of the suspect salmon, she began to
suffer nausea, itchy ears, swelling of her face, and stomach pain.
Ultimately, her condition grew so worrisome that she went to the emergency
room for treatment.
Just a little can damage
The woman had never broken out after eating fresh salmon or other fish. But
she had endured two previous bouts of anaphylaxis, or hypersensitivity, to
milk products that she had accidentally eaten.
Koppelman's team contacted the maker of the lox and learned that the recipe
contained a small amount of casein -- about a thousandth part by weight.
"Such small quantities of milk protein are capable of inducing an allergic
reaction in allergic patients," the authors write.
Dr. Clifton Furukawa, an allergy specialist at the University of Washington
School of Medicine in Seattle, says about 1 percent to 3 percent of
children are allergic to milk protein. The reaction typically ebbs over
time, although about 0.5 percent of adults never lose it, Furukawa says.
Accidental reactions to milk protein caused by poor labeling was once
widespread in the United States, but Furukawa says that over the last
decade the American food industry has worked hard to prevent such problems.
"Labeling has gotten much more cooperative in the U.S.," he says.
What To Do
Even so, Dr. Scott Sicherer, a pediatric allergist at Mount Sinai School of
Medicine in New York City, says people with acute milk allergies need to be
particularly wary of even trace amounts of casein.
The protein is often present in faint residue from milk that's processed in
food machinery. If a manufacturer then uses the same machines to make
another product -- say, apple juice -- minute quantities of casein can turn
up in that, too.
Sicherer says companies have an obligation to notify consumers that their
products might contain casein, but some don't provide such information,
leaving allergic customers to find out the hard way.
Food for thought: The phrase "natural flavoring" often refers to milk
protein. If you have severe allergies to casein and see this term on a
product label, call the manufacturer to make sure the protein isn't present
before you eat, says Sicherer.
To learn more about food allergies, visit the National Institute of Allergy
and Infectious Diseases or the Food Allergy Network.

SOURCES: Interviews with Scott Sicherer, M.D., assistant professor of
pediatrics, Mount Sinai School of Medicine, and researcher, Jaffe Food
Allergy Research Institute, New York City, and Clifton Furukawa, M.D.,
clinical professor of pediatrics, University of Washington School of
Medicine, Seattle; Dec. 18/25, 1999 The Lancet