Q01049: Evaluation of quantitative real-time PCR (QRT-PCR) to determine the presence of meat species in processed vegetarian foods

Study Duration: May 2001 to June 2003

Contractor: RHM Technology Ltd

Convenience vegetarian foods are forming an increasing part of the retail sales. There is a need for a sensitive and robust method to detect the adventitious or fraudulent contamination of these products hence reassuring vegetarians and ethnic minorities that they are indeed purchasing food of true vegetarian origin. There are a large number of established methods for the detection of meat species and products in food analyses. However, many of these methods are only applicable to raw or non-degraded meat. Quantitative Real-time Polymerase Chain Reaction (Q-PCR) has a larger potential in this area and the number of analyses can be dramatically increased. In addition, Q-PCR is well suited to the amplification of DNA that has been highly degraded as a result of processing and which would not yield a product following standard PCR. This work will also compliment work in Q01050 and the contractors will be in close liaison.

The objective of the project is to develop a method that provides the ability to identify the presence of meat species in processed vegetarian foods using Quantitative Real Time PCR. To address the problems of sensitivity an initial primer/probe system based on high-copy number sequences will be used to detect homologous DNA from degraded meat in processed vegetarian products. Samples of typical vegetarian dishes containing a known amount of added meats of common species will be produced using a range of processing conditions to investigate the scope and robustness of the method.

Food contaminated with animal by-products is unacceptable to vegetarians as well as many ethnic groups. It is also recognised that unacceptable adulterating species varies with ethnic group. To date, no satisfactory methods have been developed to detect the adulteration of vegetable products with products of animal origin.

Primers for the detection of beef, chicken, turkey, sheep and pig were developed. These were used to develop a PCR based qualitative method capable of characterising animal species in vegetable products at levels of about 0.05%.

The analysis of commercial products showed evidence of very occasional low level contamination consistent with ineffective cleaning procedures by manufacturers.

Studies aimed at quantifying the adulteration of vegetarian foods by meat have shown reasonable success if the food analysed does not contain dairy produce.

The method may be used by manufacturers and suppliers to ensure quality control procedures are effective. The method may also be used by the Agency in a future authenticity survey of vegetarian food, although further work is needed if quantification of contaminating species is to be achieved.

The final report will be available from the Food Standards Agency library once papers resulting from this project have been published in peer-reviewed scientific journals.

Contact: For any enquiries concerning this research project, please contact the relevant Programme contact or email science@foodstandards.gsi.gov.uk