University of Minnesota
July 20, 2009
A new test kit based on University research detects melamine, a chemical that has killed children when added to infant formula.
By Deane Morrison
Last year six Chinese children died and 150,000 were hospitalized after drinking infant formula tainted with melamine, a cheap chemical that masquerades as protein when added to food products.
But now a new test kit for the chemical will help protect human and pet health. The kit utilizes an enzyme, discovered and supplied by University of Minnesota researchers, that quickly produces a color change in samples of melamine-laced milk, powdered milk, cream, and other food products. The kit will soon be field tested by BIOO Scientific, a Texas-based company specializing in food safety testing.
The test kit answers a call from the World Health Organization for a simple, inexpensive means of detecting melamine in foods, formula, and other liquids.
“If a sample has a lot of melamine, you would see a blue color in a second,” says Lawrence Wackett, a professor in the University’s BioTechnology Institute (BTI). “If you want to [measure the quantity of melamine], you let it react for a half hour for full color development.” Traditional detection required expensive equipment and a few days’ turnaround.
“The test is specific for melamine, Wackett adds. It will most likely be used in China and other Asian countries, where BIOO Scientific does a lot of business.
“We helped the company by providing the enzyme and expertise,” Wackett says.
Wackett and BTI professor Michael Sadowsky became involved in the project because they lead a research group that studies the biodegradation of herbicides that bear a chemical resemblance to melamine. Research associate Jennifer Seffernick found the enzyme in a soil bacterium.
“A few environmental researchers discovered something that can really protect human and pet health.”
The researchers published a paper on the enzyme in 2001. It went virtually unnoticed until about a year ago, when Wackett started getting calls from companies that had found the paper in the wake of the melamine scandal. The story illustrates the importance of research that’s not directed toward a particular goal, or at least not the one to which it is eventually is applied, the researchers say.
“A few environmental researchers discovered something that can really protect human and pet health,” Sadowsky notes. Adds Wackett, “Products like LEDs and flat-screen TVs came from fundamental research on materials and [chemistry]. We need a fundamental understanding of how things work. That leads to the next generation of ways to attack disease and make products.”
The reason melamine was added to milk used for drinking and infant formula was to confound tests for the protein content of milk and milk products. No one can fool a regulator by simply shorting the amount of milk and then claiming the milk must have been low in protein; that’s because, Wackett says, cows all over the world produce milk with a uniform protein content.
But the cheaters knew that the test for protein actually measures nitrogen, a key component of protein.
“Unscrupulous people were diluting milk with water and throwing in melamine, which is two-thirds nitrogen by weight,” says Wackett. Sometimes so much was added that the melamine couldn’t completely dissolve, and it formed a milky white suspension.
Melamine was originally used to make durable plastic for housewares and countertops. It is also widely used as an additive to concrete. When ingested, melamine leads to the deposition of crystals that clog kidney tubules and may cause kidney failure. In addition to the human toll, about a thousand cats and dogs in the United States died from melamine-laced pet food in 2007.
The BTI researchers have cloned the gene for the enzyme and developed a way to purify it. Because BIOO Scientific lacks a pilot plant to produce it, the company will purchase the enzyme from BTI as needed.
Read more about the University's BioTechnology Institute.