Although eating horse meat is normal in many parts of the world, in other places, such as Britain, it rates almost on the same level as eating the family dog. So when it was discovered last year that horse meat was being passed off as beef, it literally put a lot of people off their dinner. To prevent a repeat of the episode, the Institute of Food Research (IFR) in Norwich and Oxford Instruments have developed a portable detector that can differentiate between horse meat and beef in about 10 minutes, yet is inexpensive and simple to use.
When the horse meat scandal broke in 2013, it was a major story that rocked the agricultural sector and the British government. Horse meat was found in frozen beef burgers and a number of other foods, such as frozen lasagnas. It forced the recall of millions of pounds worth of meat products and sparked a major review of government regulations of the food industry, safety testing procedures, and the vulnerability of food chains extending into Eastern Europe to corruption and adulteration.
The scandal demonstrated that some sort of scientific test was needed to back up the government regulations and organizational controls to ensure that the meat inside a package matches the label. Regulations can have gaps in them and a chain of supply can show all the proper forms signed, the boxes checked, and the t's crossed, yet still conceal a fraud. What was needed was an objective way of spot checking the meat itself to make sure it's what it is claimed to be.
The usual way of telling beef from horse meat is by DNA testing, but the procedure is slow, expensive, prone to contamination, and not suitable for a high-volume business like meat processing. Worse, the procedure was hardly portable.
Developed by IFR and Oxford Instruments under funding from Innovate UK and the Biotechnology and Biological Sciences Research Council (BBSRC), the detector, called Pulsar, is based on the fact that cattle and horses have different digestive systems, so they produce different triglyceride fats that show up in their meat. Pulsar is a high-resolution, bench-top 60 MHz Nuclear Magnetic Resonance (NMR) spectroscope that's based on standard MRI technology, but unlike conventional MRI scanners used in hospitals, the Pulsar has permanent magnets instead of supercooled coils, so its design is much simpler, smaller, and portable.
Operation is relatively simple. A sample of meat, which can be fresh or thawed, is put through a simple chloroform-based extraction technique. Then the sample is inserted into the Pulsar, where the magnetic resonance signature of the target fats are recorded and analyzed in a few minutes by software developed by IFR.
According to IFR, tests of the Pulsar were carried out at a leading, but unnamed, meat processor, where Pulsar turned out to be as accurate as DNA screening, but faster, cheaper, and suitable for high-volume testing of raw meat at the abattoir. In future, the team hopes to widen the range of the the detector, so it can identify other meats, such as pork and lamb.
"It’s a stroke of luck really that some of the most important meats turn out to have fat signatures that we can tell apart so easily with this method," says Dr Kate Kemsley of IFR. "It’s been very satisfying to see results from a real industrial setting sit right on top of those we generated in our two labs. We think this testing method should work well at key points in the supply chain, say at meat wholesalers and processors."
The team's findings were published in Food Chemistry.