Technologies for Food Detectives
Molecular, genetic, and spectroscopic technologies are putting a spotlight on the food supply chain.
In Europe, concerns about health, taste, and origin collide in olive oil. Its high value, complex flavor, and ever-growing list of known health benefits, combined with a long history of fakes and adulteration, have made it one of three focus foods in a 12-million-euro ($13 million) European Union research project on high-tech tracking of food quality and provenance. (The other two are Scotch whisky and fish.) Paul Brereton, coördinator of the project, says that assuring food’s integrity is in some ways more complex than assuring its safety: instead of just looking for a few known toxins, fighters of food fraud must detect something harder to identify: any adulteration or substitution that might occur to a crook.
“What industry needs are ways of measuring change in simplistic terms,” Brereton says. “Instead of profiling the contaminant, you profile the food. That’s the big challenge, the scientific challenge.”
In olive oil the researchers will use genetic and molecular markers to make ever finer distinctions between olive cultivars and regions within European countries, which can have their own chemical differences, according to chemist Diego Luís García-González of the Spanish National Research Council’s Institute on Fat in Seville. García-González is a leader of a team developing high-speed techniques for identifying the geographic origin of olive oil. “Obviously, an olive tree planted in a mountain zone won’t be the same as an olive tree planted in a valley. And that chemical difference is observable,” he says.
Food traceability and adulteration have mattered to Mediterranean governments for millennia. Archaeologists at the Monte Testaccio site in central Rome regularly recover broken amphora shards with handwritten labels identifying olive oil producers. Forty-four-hundred-year-old cuneiform tablets describe the work of royal olive oil inspectors in Ebla, in modern Syria. Following a 1981 court case in Madrid alleging that a company mixed a factory lubricant into olive oil, sickening 700 Spaniards, the Institute on Fat began developing national quality control methods, including an expert panel that still convenes to taste, sniff, and rate olive oils.
“The problem is it’s a lot of labor,” García-González says. So he and others are developing new methods that replace human tasting panels with genetic testing. They can do that because olive oil contains some of the genetic material of its parent plant. Researchers aim to compare genetic sequences in plastids—tiny chemical-producing components of plant cells, which are less likely to suffer contamination—with sequences in suspect olive oils. If DNA found in the suspect oil doesn’t match that of trees at the supposed origin of the oil, buyers could reject it. Such tests take perhaps an hour or two to run and cost a tenth what they might have a decade ago. Similarly, mass spectrometers, which can precisely analyze chemicals in a sample, are getting smaller and cheaper, making them more portable and useful for checking food along the supply chain, says agricultural chemist Sue Ebeler of the University of California, Davis. Mass spectrometers are sensitive to even trace amounts of molecules, so if a food has well-known components, they could detect any substitution or contaminant in it.
Such technology can ensure that people avoid a food they are allergic to, help them avoid genetically modified foods if they prefer, and guarantee that consumers are eating the type of fish they paid for.
Tracing the identity of a fish from the net to a plate is difficult and expensive: fishermen often capture similar-looking species, and exporters may group them together before processing and exporting. And fish identities are fluid. The name “grouper,” for example, covers 66 species, according to the U.S. Food and Drug Administration. And not all are in the same genus.
“What the FDA calls a grouper and what evolution calls a grouper—there’s a little bit of disparity involved,” says microbiologist Bob Ulrich, chief technology officer of the food testing company PureMolecular in St. Petersburg, Florida.
Confirming species identity is a first step in countering food fraud. Next is nailing down the specific origin of a food product. García-González and his colleagues at the Institute on Fat are developing a database of important olive cultivars and their chemical differences, but growers and food distributors can also introduce their own tracers. Chemical engineer Robert Grass at the Swiss Federal Institute of Technology in Zurich has developed a way of encapsulating a small amount of genetic material in microscopic magnetic capsules. Buyers at different points in the supply chain could use a magnet to extract some DNA-carrying capsules and then read the DNA to confirm its identity with a cheap test.
Ebeler says scientists are “still at the very early stages” when it comes to making sure consumers know exactly where their food comes from. And big challenges remain. Processed foods with multiple ingredients, such as frozen lasagna, present a much more complex problem than a single grouper.
Success will bring a clear economic reward, however. Premium-priced olive oils are just one example of the valuable exports these kinds of technology could support. “The European Union is conscious that one of its advantages [in the food export market] is its security and reputation,” García-González says.
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