Q01046: Authentication of milk and milk products using surface enhanced laser desorption/ionisation
Tuesday 12 August 2003
This research project aims to determine whether a new method is suitable for use in determining whether specialist milk and milk products have been adulterated with cow's milk.
Background
The sale of milk and milk products that have originated from goat, sheep or buffalo has increased in recent years. These specialist products attract a premium price and are therefore targets for adulteration with more readily available and less expensive cow's milk. The same holds true for well-established traditional cheeses such as Buffalo mozzarella and sheep Feta cheese. The development of a method for the identification of the source of the product is therefore essential for the detection of fraud.
Present identification methods employed in the detection of cow's milk in sheep/goat/buffalo milk and milk products include Enzyme-Linked Immunosorbent Assay (ELISA), isoelectric focusing and Nuclear Magnetic Resonance (NMR). These techniques are time consuming for both the sample preparation and the analysis. More recently a method of detection and quantification using capillary electrophoresis has been reported. This is a quicker method but peak detection may prove to be a problem on older cheeses due to degradation products.
Research Approach
This project is designed to establish whether the new Surface-Enhanced Laser Desorption/Ionisation (SELDI)-based state-of-the-art technology would be useful in the field of food authentication. SELDI is a relatively new development in the field of mass spectrometry that is able to give reproducible and accurate information on the molecular mass of proteins found in complex mixtures. The technique is capable of the detection and analyses of proteins at low levels and therefore of detecting adulteration of specialist milk with cow's milk. The procedure is fast and requires relatively little in the way of sample preparation.
The research approach will involve
1. Production of species specific SELDI Protein Profiles from cow, buffalo, sheep and goat milk. Where possible more than one breed will be tested)
2. Ascertain the limits of detection of the presence of one milk in another
3. Production of species specific SELDI Protein Profiles of whey proteins from cheese produced from these different milks