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Neigh need for NGS for meat testing- in the mane, PCR is enough!

Horsemeat testing is continuing to show that contamination, while lower than when first reported, is still not, well, stable!

There’s been horse meat around for donkey’s years..!

The UK Food Standards Agency (FSA) showed at the end of March that it’s testing found 352 samples out of 362 contained less than 1% horsemeat. Of the remaining 10, three samples contained pig DNA and two contained horsemeat. Meanwhile, 100 kg of ‘diced beef’ imported from Hungary was, in fact, horsemeat. If nothing else, the incidents underscore the important role played by PCR testing (and the possibility of using sequencing data).

Just take a D-N-Neigh sample..!

Most DNA tests for horsemeat have been of the routine PCR-based marker search variety. You just take DNA samples from the meat, isolate the DNA fragments and amplify with PCR. After the PCR, it is then possible to identify horse-specific markers.

The International Society of Animal Genetics has a set of single tandem repeats (STRs) for all horses, including AHT4, AHT5, HMS1, HMS2, HMS6, HMS7, HTG4, HTG6, HTG7, and VHL20. Commercial testers use these, as well as additional STRs at the University of Kentucky and the University of California, Davis. What’s not routine is the regular use of PCR to search for horse markers.

Too blinkered to know what’s in there..!

One could conceivably test for millions of markers indicating thousands of animal species that could adulterate food; the question is- how much goat, cat, or canary will we tolerate in our food?!

Genome sequencing opens the (stable) door..!

Next Generation Sequencing would certainly identify a horse (its genome was sequenced about five years ago), but would be rather expensive for routine testing. However, NGS is not foreign to the stable. Many horse breeders use NGS techniques to identify the sirage of a new racehorse or show animal. In addition, the horse genome, which was finally sequenced in 2009, has opened the door to understanding how certain coat colors are inherited (black is dominant to red, but the ‘agouti’ gene will ensure that black pigment only exists in the mane, feet and tail, for example), which is important for breeders.

Just as important, the sequence can help pinpoint (and help breeders avoid) genetic diseases such as HYPP, which causes paralysis in quarter horses, and JEB, a severe skin disease in Belgian draft horses.

Would you like mayo-neighs on that..?!

So, unless you really want to know if your burger or lasagna contains a descendant of Man o’ War or Red Rum, PCR-amplification will do the identifying trick for now.


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