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The International Organization for Standardization (ISO) logo that certifies forensic products and tools have met the ISO's standard for preventing contamination in the manufacturing process. (Image: Courtesy of Promega)

The “Phantom of Heilbronn” was a woman whose DNA showed up at dozens of scenes of brutal deaths in Germany, Austria and France over two decades. But her violence was baffling: it followed no pattern, the accomplices in her crimes denied her very existence and she was never seen on any surveillance videos.

After eight years, and 16,000 hours of police overtime, the police found their “Phantom” in 2009: she was a worker at the factory producing the cotton swabs used at all the crime scenes. DNA contamination of forensic tools used by police had placed the faceless woman at the disconnected crime scenes.

Further studies have since shown that DNA mixtures and secondary transfer have complicated forensic analysis of genetic material at potentially every crime scene. The International Organization for Standardization put forth a standard last year to try and prevent such contamination.

Promega announced Tuesday it was the first forensic manufacturer to achieve the ISO standard. (The ISO standard was the product of an international collaboration which included two Promega scientists and members of the Arkansas State Crime Laboratory representing the United States. Ultimately, the ISO 18385 standard was based on Australian guidelines.)

The third-party certification means Promega products are now emblazoned with a “Forensic Grade” logo.

“This critical milestone is the best way for forensic laboratories to ensure that products claimed to be produced under published ISO 18385 guidelines are indeed meeting those expectations,” said Charles York, a vice president of manufacturing at the Wisconsin-based company.

The company revised its quality control testing in response to the standard. A key change was treating plastics with ethylene oxide to sterilize plastic items like tubes and bottles used in DNA extraction and quantitation, and STR exemplification reagents.

“The treatment is very effective at destroying DNA and rending it unamplifiable in PCR and is an effective post-production treatment method for minimizing DNA contamination on plastics,” the company explains.

Whether that ethylene oxide treatment would prevent the appearance of another “Phantom of Heilbronn” remains unclear.

Linzi Wilson-Wilde, the director of the National Institute for Forensic Science in Australia and New Zealand, spoke to ISO about the importance of meeting the new standard last year.

“Implementing ISO 18385 will give confidence to forensic scientists that the products they use are fit for purpose and appropriate measures have been taken to significantly reduce contamination, thereby diminishing the number of extraneous DNA contributing to DNA profiles, potentially making results easier to interpret,” she said. “This all leads to greater confidence in forensic science results by police and the courts.”

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