FDA's Forensic Center: Speedy, Sophisticated Sleuthing
Stehlin, Isadora B., FDA Consumer
By the time the mouse and its Pepsican coffin reached FDA, Fred L. Fricke and his team of chemists and microbiologists didn't have much to work with.
The mouse, found dead in a can of Diet Pepsi in New York, had already been examined by Pepsi officials. From there it went to a veterinarian on the East Coast. Next stop was a pathologist in Utah. Finally, the dissected mouse was sent to Fricke at FDA's Forensic Chemistry Center in Cincinnati.
Fortunately, the mouse's teeth were still intact. "We measured the spacing between the teeth and the pattern of bite marks on the can," explains Karen A. Wolnik, director of the center's inorganic chemistry branch. "From those measurements it was determined that his lower teeth had left marks on the inside of the can and his upper teeth had gnawed the outside, right at the pull-tab opening."
Wolnik says that pattern demonstrated the mouse had been inside the can when it bit the lid. But because the can lid with the pull-tab opening is in one intact piece throughout manufacturing, the mouse couldn't have bitten the lid or gotten into the can until after it was opened. The evidence was used to convict a tamperer who had falsely claimed to have found the mouse inside the can when she opened it. (Under the Federal Anti-Tampering Act, it is a felony to tamper with foods, drugs, devices, cosmetics, and other consumer products.)
"Every week we get something that's suspected tampering," says Fricke, director of the forensic center. "It never slows down."
FDA established the center in 1989 to provide the agency with a team of forensic science experts who can respond immediately to all tampering incidents and provide expert advice and scientific evidence to FDA officials. The 30 chemists and three biologists unravel the scientific mysteries of tamperings and other criminal activities involving FDA-regulated products through careful observation and high-tech instruments.
The center has inorganic chemistry and organic chemistry branches. The organic branch uses organic analytical detection methods--such as infrared spectroscopy, gas and liquid chromatography, and mass spectrometry--to separate and identify the components of mixtures. The inorganic branch uses tools such as digital image analysis and scanning electron microscopy to detect physical evidence of tampering or counterfeiting, and ion chromatography, atomic absorption, and inductively coupled plasma spectrometry to measure inorganic components of mixtures. (See accompanying article.)
Most cases require the expertise of both branches. "There's no division [of responsibilities] that's really sacred," says R. Duane Satzger, director of the organic branch. "When we get a case, both branches sit down and talk about it and decide how to address the situation."
For example, he explains, a syringe might first be examined by the inorganic group. Wolnik's staff would use light microscopy to examine the syringe. If, during this examination, they observed some kind of liquid in the needle of the syringe, Satzger's staff would use chromatographs or mass spectrographs to identify the liquid. Electron microscopy might be used to detect decomposition and other physical changes to the syringe that might have occurred if the syringe had been submerged in soda or come in contact with poison.
Tylenol, Grapes and Cyanide
In 1980, Fricke, Satzger and Wolnik worked at the forensic center's predecessor, FDA's Elemental Analysis Research Center in Cincinnati, where they conducted research and developed procedures for detecting toxic and nutritional trace elements in foods and drugs.
In 1982, when the first Tylenol tampering occurred, FDA chemists developed elemental "fingerprinting" techniques that allowed the authorities to trace the cyanide back to the manufacturer and the distributor. "The identity and relative amounts of various elemental constituents in a suspect sample form a distinct pattern that can be used for comparison with other samples, much like actual fingerprints," explains Wolnik. …