‘MasSpec Pen’ Can Uncover Food Fraud in 15 Seconds

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Europe’s 2013 horse meat scandal—in which foods advertised and sold as beef actually contained horse meat—revealed a major breakdown in the traceability of the food supply chain. In this case, it wasn’t particularly dangerous, but, overall, food fraud is a serious problem that can result in fatalities, not to mention the infringement of religious and cultural restrictions.

Current methods, like liquid chromatography mass spectrometry (LC-MS), are accurate but expensive and time-consuming. Now, researchers at the University of Texas at Austin have developed a method that can authenticate the type and purity of meat and fish samples in as little as 15 seconds, without harming the sample.

Livia Eberlin and colleagues’ handheld “MasSpec Pen” extracts compounds from a sample’s surface, and then analyzes them on an attached mass spectrometer. A 20-µL droplet of solvent is enough to extract sufficient amounts of molecules within 3 seconds with no need for pre-processing and no harm done to the samples’ surface during liquid extraction.

To test the effectiveness of the device, the research team used it to analyze and classify five types of raw meat and fish, as well as mixed meat samples. According to their paper published in ACS’ Journal of Agricultural and Food Chemistry, the MasSpec Pen consistently demonstrated 100% accuracy across all food samples.

For example, the MasSpec Pen picked up the differences in the molecular species present in grain-fed versus grass-fed beef. The two meats are prone to food adulteration as they look the same but grass-fed beef is more expensive, leading adulterers to mislabel grain-fed beef as its more costly counterpart to haul in a larger profit. This happens with venison, as well, which is even less expensive than grain-fed beef—and not even the same species.

Using 176 spectra acquired from 20 samples to form the basis of an authentication test system, the researchers demonstrated an accuracy of 95% for grain- versus grass-fed beef and 100% for grain-fed beef versus venison.

Similar results were seen in mixed meat samples when the researchers mixed varying percentages—0, 25, 50, 75 and 100%—of grain-fed beef as an adulterant into samples of grass-fed beef or venison. An overall 93% per spectrum accuracy and a 90% per sample accuracy was achieved, although the scientists say additional studies using lower percentages of substituted meat are necessary to validate the findings.

For raw fish samples, the MasSpec Pen detected distinct mass spectra profiles for each fish type: steelhead trout, sockeye salmon, Atlantic salmon, cod, and halibut. Overall accuracy was 84%, but different values were seen depending on classification model. For example, the device yielded 100% accuracy when distinguishing halibut and cod, which are very visually similar and prone to food adulteration. Ninety percent accuracy was achieved when comparing steelhead trout, sockeye salmon and Atlantic salmon, all of which are also visually similar and commonly substituted in fish fraud crimes.

Ultimately, the study shows that the MasSpec Pen is a reliable, robust method for food authentication that can be employed incredibly quickly.

“At a minimum, the 15 second testing time per sample provided by the MasSpec Pen is ∼240 times faster than LC-MS (considering a total analysis time of 1 h/sample) and ∼720 times faster than PCR (considering a total analysis time of 3 h/sample),” the researchers write in their paper.

The University of Texas at Austin research team says they will expand their study to include additional me and meat products, such as wild fish and beef products from other countries. They are also looking into integrating the MasSpec Pen with a portable ion trap mass spectrometer to enable field testing.

Photo: The MasSpec Pen can authenticate the type and purity of meat samples in as little as 15 seconds. Credit: Adapted from Journal of Agricultural and Food Chemistry 2021, DOI: 10.1021/acs.jafc.0c07830