Andrew Tingey, Reading Scientific Services Ltd., The Lord Zuckerman Research Centre, Whiteknights, PO Box 234, Reading RG6 6LA, UK
One of the most topical issues in the food industry is the use of genetically modified organisms (GMOs) in agriculture and food production. Demands from consumers, particularly in Europe, for clear labeling of products that contain genetically modified (GM) plants or their derivatives have given rise to a requirement for analytical methods that can detect GM material. Within Europe, producers of foodstuffs must comply with European regulations regarding labeling of products, including a recent regulation, (EC) 49/2000, that sets a maximum threshold of 1% on certain GM ingredients. With the introduction of the threshold, quantitative methods of GMO detection have become increasingly important.
There are 2 basic analytical methods for the detection of GM plants: detection of the novel DNA used in the genetic modification, or detection by ELISA of novel proteins produced as a result of the modification. The polymerase chain reaction (PCR*) has remained the method of choice for GMO detection, because DNA is more likely to survive food processing than proteins. The introduction of real-time PCR has made the accurate quantitation of the starting amount of DNA targets possible and its application to the quantitation of GMOs in food is becoming more important. Aside from quantitation, real-time PCR offers another advantage for the analytical molecular biology lab because it requires no postamplification handling of samples, reducing the risk of contaminating the laboratory and analytical samples with PCR products.
In real-time PCR, a