GM testing expert, Dr Andrew Tingey of RSSL, has warned the food industry against overstating claims for the accuracy of GM test results.
Dr Tingey claimed: “It is now possible to detect very low levels of GM ingredients in all kinds of foods. However, even the best available methods for quantifying the amounts found have a relative accuracy of plus or minus ten per cent. To rely on any results that do not accept this margin of error is an act of folly. It leaves the industry at risk of breaking the law on labelling.”
RSSL was the first laboratory in the UK to offer a commercial testing service on food from supermarket shelves, based on PCR technology, and was quickly established as the UK’s leading GM testing lab. The company has recently invested in new technology and is about to launch a fully validated ‘real-time’ PCR service for GM testing. According to Dr Roger Evans, science director at RSSL: “We have spent several months validating this method and are now totally convinced it will produce the best results available in the market.”
‘Real-time’ PCR differs from traditional PCR in one important respect. Both methods involve the creation of multiple copies of a target strand of DNA.
In traditional PCR, these multiple copies are separated from the rest of the DNA present using the technique of gel electrophoresis. In real-time PCR, the gel separation step is not needed. Rather, at the same time as the copies of DNA are produced, a fluorescent marker is also released in direct proportion to the amount of DNA present. Measuring the fluorescence level as it rises (ie, in real time) gives a quantitative assessment of the DNA present.
Dr Tingey went on to conclude: “The EU allows goods to be labelled as GM free if the GM content is below one per cent. Hence the industry needs to get the best possible measure of the GM content of its ingredients and products. However, where results are on or around that level, it is vital to recognise there is a margin of error that means that good news today could well mean bad news tomorrow.
“If a product is just below the limit on one test, it could exceed the limit if tested again. So it is vital that the food industry understands there are limitations to any scientific method and doesn’t get charmed by what may appear to be greater levels of accuracy simply because results can be quoted with a string of decimal places.
“The extra numbers are irrelevant and misleading. If the food industry wants to regain the confidence of consumers then it must use credible science to generate its results. Otherwise, it will only be a matter of time before specific results are discredited, at which point, everyone will come under suspicion.”
By Stephen Blake
Editor of Food Industry News