Authenticity testing

We are at the forefront of developing methods to authenticate food materials using DNA- and protein-based tests. We concentrate on examples of importance to industry and government, including the presence or absence of genetically modified material, the identification of a range of fish, meat and plant species including basmati rice and fruit juice, and the detection of nut allergens.

As Steve Garrett of CCFRA’s Chemistry and Biochemistry Department explains “The approaches we use demonstrate our strength in identifying techniques from other fields and applying them to food and drink. We work closely with state-of-the-art equipment manufacturers to help develop simple procedures that can be used within industry. A good example is the lab-on-a-chip capillary electrophoresis system which we applied to fish species identification with funding from the Food Standards Agency. As well as offering a service ourselves, the system has been adopted by a number of UK enforcement laboratories to be used for surveillance and enforcement purposes.”

Another recently validated method will help ensure that virgin olive oils have not been adulterated with cheaper hazelnut oil for fraudulent sale. The two are particularly difficult to distinguish using standard analytical techniques. The new approach, again developed with the support of the Food Standards Agency, enables detection of hazelnut DNA using the polymerase chain reaction (real-time PCR). The sensitivity and accuracy of the method, and overall success of the approach, suggest that it could also be applied to other oils.

Lab-on-a-chip can also be used to distinguish between wheat varieties on the basis of their protein profiles, as Dhan Bhandari of CCFRA’s Cereals and Milling Department explains: “The traditional approach of acid polyacrylamide gel electrophoresis requires skilled operators and involves potentially hazardous chemicals, whereas lab-on-a-chip is easy to use and takes less than 50 minutes, making it most suitable for use in mill intake and food testing laboratories. An optimised system developed through a series of nabim-funded projects will enable millers to make more confident decisions in accepting grain consignments, and could become widely accepted as an effective policing tool within the grain industry.”

Looking ahead, these approaches are likely to be complemented by bioinformatics - using the power of computers to analyse biological information. Comparing publicly available DNA sequence information with that generated from authentic, reference and unknown samples, we were able to classify unknown anchovy samples according to their geographical origin - namely Peruvian, Japanese or Argentine clusters. A similar approach was used to help companies identify particular species of clam and prawn. With applications to any plant, animal or microbial species as well as in protein analysis, protein structure prediction and microbial typing, this type of approach is likely to find a wide range of applications relevant to the food industry.