The Japanese desire to eat pork from a rare English pig breed has led to the development of a DNA-tracing technology to track the entire production process.
Pork from black pigs commands a premium in Japan
The meat from black-skinned Berkshires is known as kurobuta but there is more of this prized pork being sold in shops than there are animals to supply it.
Japan's Sygen International, working with UK scientists, has now developed a genetic test to spot genuine kurobuta.
The procedure can be used to trace meat all the way back to the farm of origin.
"The pork is so highly prized that Japanese kurobuta is sold for two or three times the price of other types of pork," Dr Graham Plastow, a geneticist with Sygen, told BBC World Service's Science In Action programme.
"It became clear that in Japan, there was more kurobuta on the shelves than there were pigs to produce it, and so the Japanese were interested in using DNA to verify the breed origin of our kurobuta."
Pig in Japan
Sygen International produces and sells black pigs in Japan, and set up a research project in Cambridge which came up with the way of identifying whether meat sold as kurobuta really was from black-skinned pigs.
They used DNA fingerprinting of the type more usually used for forensics, but based on the breed, rather than individuals.
Dr Plastow explained that the Berkshire pig has very specific characteristics, and as a result a key could be drawn up to identify its products.
Scientists can now modify the genetics of pigs
"Is the pig black? Yes - it might be a Berkshire, no - it isn't a Berkshire. You work your way down the key until you have the answer," he said.
"In that case, we have been able to find the genes that are involved in variation in colour or other characteristics and then we find the variation in those genes that explain the physical characteristic that we're using in our key."
Pigs have played key roles in a number of major cell-technology developments in recent years, including the cloning of pigs and the production of "knock-out" pigs which are gene-altered so that their organs will not be rejected if put in a human.
And the Berkshires test had immediate implications for the pig industry in general, said Mick Sloyan, chief executive of the British Pig Executive.
He explained that current records only allow a product in a shop - for example, bacon in a supermarket - to be traced on a "batch" basis. This would relate to the number of pigs that came into a processor on a particular day.
"Where DNA could help is going back even further," he added. "[It can] probably get you back to the individual farm."
One Canadian company, Maple Leaf Foods, is already close to perfecting this technique.
Dr John Webb, director of genetics and science at Maple Leaf, said that they did not trace to the individual pig that was slaughtered, but to its mother; it would be too expensive to DNA type every pig.
He added that all the mothers who contribute to a plant are now DNA typed.
"You collect a blood sample, you DNA type them, and you put it into a database," he stated.
"When you have a problem with meat, or when you want to check the origin, you simply DNA type the meat and you run a search on the database, so that if a piece of meat arrives in Japan, it can easily be matched to those sows on the database."