After BSE, laser spectrometry looks set to ease policing of contaminated feed.

Fragments of gelatine could reveal contamination of cattle feed with meat and bone meal (MBM), claim analytical chemists looking for ways to police UK government restrictions in the wake of the BSE crisis.

Raj Patel and his team at the University of London have developed a detection method that uses a specialised form of mass spectrometry to identify gelatine, a protein similar to collagen that is found only in animal tissues.

Feeding animal protein to cattle caused the BSE epidemic in the UK's national herd more than a decade ago and, according to some estimates, cost the cattle industry around £6000 million. The disease has also been linked to the emergence of new-variant CJD in humans.

Scientists currently use genetic testing and microscopy to enforce the MBM ban but these methods are expensive and lack sensitivity, according to the UK Department for Environment, Food and Rural Affairs (DEFRA), which is funding the new research.

Patel and his research team hope to solve these problems using a newly developed biochemical technique and MALDI-TOF MS (matrix-assisted laser desorption ionisation time-of-flight mass spectrometry).

Patel uses a chemical digest to 'slice up' the proteins in a sample of cattle feed. These peptide fragments are then analysed by MALDI-TOF MS to give a characteristic 'fingerprint'.

The advantage of the technique lies in the spectrometer's ability to ionise very large molecules, such as proteins and peptides.

'Patel and his group have demonstrated the ability of mass spectrometry . to detect minute quantities of processed animal protein in animal feed,' notes Neil Oldham, manager of mass spectrometry at the University of Oxford. 'Once these characteristic peptides are fully identified, this approach could open the way for a rapid and reliable screening programme.'

Ian Farrell