Tracing meat with clever chips
32 different kinds of animal species. The DNA-based scheme is
currently being examined by European food regulatory bodies as a
possible means of ensuring that a food product contains exactly
what it says on the label.
Possible food production applications include identifying whether chicken has been bulked up with beef or pork products, or whether top-of-the-range beefburgers are really made from prime cuts of beef.
There are obvious food safety applications as well. The test could be used to determine whether products are infected with unwanted types of meat, or whether beef is being illegally added to cattle feed.
The technology is pretty smart. Each chip is coated with segments of DNA unique to each species, and arranged in zones. DNA strands from the food sample are transcribed into RNA and tagged with fluorescent chemicals.
These are then brushed over the chip, and any matching sequences will stick together. The pattern of fluorescent zones read by a laser scanner can therefore tell scientists which species are present, and whether this corresponds to what is on the product label.
DNA microarray chips have been used experimentally for years, but Affymetrix claims that its DNA chip is the first mainstream commercial application of the technology. Thomas Schlumberger, director of clinical genetics at Affymetrix in California, is quoted in New Scientist as saying that the cost of all the equipment needed to perform the tests is around $250,000 at present, and that each test would cost $350 to $550.
The test is another example of how important traceability is becoming in the food production industry. EU legislation on food traceability comes into force in January 2005, which means that food traceability through the supply chain is going to become a legal responsibility.
Under the new laws, food producers must be able to identify products by batch, lot or consignment numbers and traceability of the product must be possible at all stages of production, processing and distribution. This means food businesses will have to be able to identify every supplier of food, feed, a food producing animal or any substance incorporated into their food/feed products.
Supermarkets and food companies might therefore be very interested in the new DNA technology as a means of keeping an eye on their suppliers.
