There is a legal requirement to quantify the amounts of all named or characterising ingredients in a food product, which is known as the Quantitative Ingredient Declaration (QUID). Consequently, in the case of meat products, each species of meat present in the food needs to be quantified separately. A validated method to detect and quantify meat content in meat products is therefore required to assist in the enforcement of QUID requirements. Previous approaches to quantify meat species using DNA-based methods have had limited success, due to the degradation of DNA during processing of the food and interference from other ingredients affecting the accuracy of quantification. <P>
The aim of this project was to investigate the feasibility of a mass spectrometry-based approach to speciate and quantify meat ingredients in a meat product by direct detection of protein fragments.
Research Approach:<BR> A method was developed and optimised for the extraction, enrichment and processing of proteins from different meat mixes, which were either fresh or heavily cooked meat. Two types of mass spectrometry were then used to identify species-specific peptide biomarkers. The use of stable isotope labelling technology was investigated for quantification of these peptides, using chicken in pork as a model system.<P>
Results and findings:<BR>Firstly, chicken-, beef- and pork-specific peptides were identified in meat extracts that could be used as potential species-specific biomarkers. A method was then developed using the chicken-specific peptide markers to identify varying levels of contaminating chicken meat in fresh and cooked pork samples. Using stable isotope labelling, it was possible to detect chicken mixed with pork in amounts as low as 0.5% in cooked meats. The overall results have confirmed the feasibility of a proteomic approach for quantification and identification of meat ingredients, although further studies to fully validate this approach for all species are needed.
<p>Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research webpage</a>.