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Agency Depends On In-House Forensic And Toxicological Expertise

FDA scientific units have compiled evidence needed for several high-profile cases

by Sophie L. Rovner
May 12, 2008 | A version of this story appeared in Volume 86, Issue 19

Credit: Chris Cone/Black Star
With the aid of a stereoscopic light microscope, one of FDA's Forensic Chemistry Center scientists isolates foreign particles from contaminated pet food.
Credit: Chris Cone/Black Star
With the aid of a stereoscopic light microscope, one of FDA's Forensic Chemistry Center scientists isolates foreign particles from contaminated pet food.

The Food & Drug Administration has investigated many incidents involving accidental or intentional contamination of food and pharmaceuticals. Two units that are key to such investigations are the Forensic Chemistry Center (FCC) and the National Center for Toxicological Research (NCTR).

FCC in Cincinnati is FDA's crime lab and it supports the agency's Office of Criminal Investigation (OCI), which investigates criminal violations of the Food, Drug & Cosmetic Act such as product tampering or pharmaceutical counterfeiting. OCI also participates in law enforcement and intelligence efforts related to threats associated with FDA-regulated products.

In addition to participating in criminal cases, FCC staff also assist in problem solving related to FDA's regulatory work. One example of this type of work is the 2007 pet food contamination case, says R. Duane Satzger, director of FCC's organic branch.

FCC had its origins in a small elemental analysis group. The group helped in the investigation of a 1982 case in which Tylenol capsules laced with cyanide killed seven Chicago-area residents. By developing a trace-contaminant profile of the cyanide in the capsules and other cyanide samples, the analytical group deduced that the cyanide in the capsules had been made by DuPont, according to a paper Satzger and his colleagues published after the incident (Anal. Chem. 1984, 56, 466A). The cyanide profiles also suggested that the tampering had occurred at the retail level and not at a Tylenol plant. The identity of the tamperer was never discovered.

The Tylenol investigation was "where our forensic work began," Satzger recalls. Then in 1989, "we got involved after cyanide had been detected in Chilean grapes, and there were threats that additional fruit from Chile had been adulterated with cyanide." The analytical group was asked to determine whether grapes could be adulterated with cyanide, whether the fruit could then survive the trip to the U.S. or would arrive spoiled, and whether the fruit would still be toxic once it arrived. Ultimately, FDA found no additional evidence that cyanide had been added to shipments from Chile.

"Shortly thereafter, FDA decided they needed a facility that would deal with threats, so they established the Forensic Chemistry Center," Satzger says. The group, which is now 55 strong, still does elemental analysis but also has a broad range of other capabilities.

More recently, FCC worked with the Centers for Disease Control & Prevention to determine why cough syrup killed more than 40 people in Panama in 2006, Satzger says. The investigators found that the cough syrup contained diethylene glycol, which is sometimes used as a cheap but illegal substitute for glycerol, explains FDA cell biologist William H. Tolleson. FCC also helped out with a 2007 incident involving counterfeit Colgate toothpaste imported from China that contained diethylene glycol.

FCC generally approaches this type of investigation by screening a product for adulterants. "When available, we'll compare a suspect product to a control product and look for differences," Satzger says. "And once we see differences, we'll use a variety of tools to identify the differences." In the 2007 pet food case, FCC relied on mass spectrometric and vibrational spectroscopic approaches, as well as optical microscopy, liquid chromatography, and enzyme-linked immunosorbent assays.

Many other FDA divisions participated in the agency's response to the pet food incident. They include FDA's Office of the Commissioner, the Office of Regulatory Affairs, the Center for Food Safety & Applied Nutrition, the Center for Veterinary Medicine, and NCTR.

NCTR was established in 1979 and is located in Jefferson, Ark. Tolleson, who works at NCTR, says the unit "performs toxicological and mechanistic studies to support the decision-making and risk-assessment responsibilities of the other FDA centers, like the Center for Veterinary Medicine."

The unit carries out "chronic and acute animal bioassays, combined with mechanistic studies, to assess the toxicity and carcinogenic potential of agents associated with FDA-regulated foods, drugs, cosmetics, and medical devices," Tolleson adds.

The center has participated in studies related to fumonisin B1, a fungal toxin that can contaminate corn products; aromatic amines found in cooked meats; and malachite green, a banned algicide that was used in aquaculture.

Scientists in NCTR's biochemical toxicology division are currently evaluating the toxicity of acrylamide, which is found in fried, starchy foods; potential endocrine-disrupting compounds such as nonylphenol and soy isoflavones; aloe vera, which is used topically or orally to treat skin and other conditions; and nanostructured materials used in sunscreens, such as titanium dioxide, Tolleson says.

NCTR's six other research divisions cover neurotoxicology, genetic and reproductive toxicology, personalized nutrition and medicine, systems toxicology, microbiology, and veterinary services. "Scientists from each of these divisions perform studies related to the safety of foods or drugs including AIDS drugs, herbal food supplements and alternative medicines, and drugs like methylphenidate that are used in children," Tolleson says. They're also investigating the development of drug resistance in microorganisms.

In short, he says, NCTR investigators "endeavor to confront the spectrum of emerging issues in toxicology challenging the FDA."

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