Researchers at the University of Milan-Bicocca are developing a portable kit based on DNA barcoding to detect food fraud, making inspections accessible not only to professional operators but also to supermarkets and consumers.
In the world of food fraud, a distinction can be made between commercial fraud and health-related fraud. The former does not pose risks to health; while no less illegal, it is far more common and frequent.
In 2024, Italy’s Central Inspectorate for Quality Protection and Fraud Prevention of Agri-Food Products inspected more than 28,500 operators and over 54,000 products, seizing almost 13 million kg of goods, with a total value exceeding €22 million (2024 ICQRF report).
An increasingly effective tool for detecting such fraud is DNA barcoding: by exploring new applications, the goal is to turn it into an anti-fraud ally not only for professionals but also for individual citizens. Before discovering what the University of Milan-Bicocca team is pioneering on this frontier, it is worth understanding what science is fighting against and what harm it seeks to prevent.
Takeaway
Dilutions and food swaps
“Generally, food fraud causes commercial harm to consumers because a cheaper species is sold under the name of a more expensive one. Those with health consequences, I believe, are mainly linked to errors and negligence in controls,” explains Jessica Frigerio, researcher at the Department of Biotechnology and Biosciences at the University of Milan-Bicocca. She lists several examples of scams that are not harmful to health but can still upset those who buy food in good faith.
The most frequent cases involve species substitution: cheaper species being sold as more expensive ones. This occurs mainly in the fish sector, to the point that in the United States, all imported fish is subjected to strict DNA barcoding checks, with special attention to salmon. Italy is only beginning to move in this direction: “At customs, we have started carrying out these checks on fish, but only in suspicious cases,” notes Frigerio, “and there are plans to extend this to spices, again using DNA barcoding.”
Among the food frauds occurring in Italy is that of yellowfin tuna treated with beetroot dye to make it resemble bluefin tuna. Many other high-value fish are deliberately substituted with cheaper, similar species in order to remain competitive, but sometimes the fraud is unintentional and stems from “some fishermen’s overconfidence in their ability to distinguish species morphologically,” says Frigerio. Due to the climate crisis, the Mediterranean now hosts species previously uncommon, making it harder to identify what is being caught.
Other frequent commercial frauds involve saffron and oregano, which are not always 100% authentic. Moving on to frauds with health implications, Frigerio cites cases where allergens are not declared, either to bypass regulations or simply out of negligence. One example is flour contaminated with mustard seeds. “It is not banned as such, but mustard is an allergen and, if present (even accidentally) it must be clearly indicated on the label,” Frigerio stresses.
Anti-fraud tests for everyone
In this world where we can easily become unwitting victims of food fraud, science is working to make a long-standing method more widely available. The challenge, according to Frigerio, is to make it accessible to everyone. She is developing rapid test kits that deliver immediate results, using colorimetry to show whether a target species is present. “Imagine a small tube containing a pink reagent into which a food sample is inserted, and the color changes depending on the result,” Frigerio explains. “Meanwhile, rapid DNA extraction techniques are essential, especially for certain products, to ensure the procedures are practical and user-friendly.”
This anti-fraud kit is designed for customs officers and others responsible for monitoring imported food, but not exclusively. Frigerio emphasizes that the ultimate goal is to make it available to companies, supermarkets, and even end consumers – empowering them to be more active and informed.
DNA barcoding, a “special investigator” for food fraud
The effort to create a kit accessible to everyone is both admirable and fascinating, but to understand why this technique matters, it is necessary to clarify its advantages in this context. First, DNA barcoding can identify a species from even tiny fragments; large amounts of material are unnecessary, and it works even on processed products. This is crucial for food fraud detection because it allows the technique to be used on items taken directly from store shelves, not just unprocessed raw materials.
DNA barcoding also delivers results quickly, without slowing down inspection processes. This is particularly useful for companies that need certainty about ingredients but cannot afford to halt production lines for hours while awaiting test results. It applies to fish as well as frozen soup mixes, flour, pasta, and other processed foods. Unlike other analyses, it identifies species rather than proteins, preventing false positives caused by the fact that different foods often share the same proteins—some of which are tolerated while others are not.
Another potential benefit of DNA-based techniques is DNA metabarcoding, which can simultaneously identify multiple species present in the same sample, essentially producing a list. For foods such as curry, this could be a real game-changer.
This series dedicated to DNA barcoding stems from the experience gained in the laboratories of the University of Milan Bicocca and the National Biodiversity Future Center thanks to the FRONTIERS program.
