German scientists checking the safety of wild boar meat sold in markets have discovered a halogenated compound that resembles a persistent organic pollutant (POP). But whereas most POPs are pesticides or other industrial chemicals, this molecule likely comes from someplace benign: a fungus that the boars eat (J. Agric. Food Chem., DOI: 10.1021/jf201128r). The work could shed light on which structural motifs make halogenated molecules toxic in the environment, experts say.
During a routine food safety analysis, Josef Hiebl of Bavaria's health and food safety department detected a contaminant in boar meat that he couldn't trace back to a known pollutant. The chemical was at much higher concentrations than persistent organic pollutants, such as the pesticide dichlorodiphenyltrichloroethane (DDT).
With Walter Vetter and technical assistant Katja Lehnert at the University of Hohenheim, Hiebl narrowed down the possible chemical suspects with gas chromatography/mass spectrometry (GC/MS) measurements. The team then synthesized a likely culprit, drosophilin A. Chemists first discovered this natural compound over 50 years ago from a family of fungi that includes mushrooms, a typical part of a boar's diet. Using GC/MS, Vetter and his colleagues analyzed drosophilin A and determined that it matched the mystery compound. The team next plans to confirm that the compound did indeed come from the boar's meals.
"We analyzed boar meat samples that were sold retail," Vetter explains. "It's very difficult to say where the samples were from and what kind of fungi were there for the boars to eat."
The study is intriguing because scientists know little about how halogenated compounds accumulate in terrestrial environments compared to marine environments, says John Kucklick of the National Institute of Standards and Technology, who measures environmental pollutants in marine life. The work might also have food safety ramifications if drosophilin A turns out to be toxic to people, he says. He also thinks it would be interesting to know if boars or people have evolved defenses against the compound, and why the fungi contain these compounds in the first place.
Drosophilin A looks like a POP, but if the compound turns out to be nontoxic to the boars, it could provide useful lessons about how to construct halogenated compounds so that they don't end up a health or environmental threat, says Gordon W. Gribble, a Dartmouth College chemist who studies halogenated natural products. "There's nothing inherently evil about a carbon-halogen bond," he adds.