New fast test method to detect food contamination developed

Large numbers of food samples can be analised for possible pathogen contamination.

The new method developed by Renato Zenobi , from ETH Zurich, is based on tests using what is called a "quadruple time-of-flight" (QTOF) mass spectrometer, a now standard laboratory instrument used for detecting pathogens on surfaces. Samples for the mass spectrometry method are normally processed in solution. The solution is first electrosprayed, with the additional aid of a desolvation gas.
The tiny droplets give rise to ions that are characteristic of the substance to be analysed and which the QTOF instrument measures.
The ETH Zurich researchers have now almost turned the principle on its head, they claim. Instead of studying the substances in the solution, they developed a method to examine the substances present in the desolvation gas assisting the spray.
With the newly-developed method nitrogen is blown from a small nozzle onto a sample surface. As the gas strikes the surface it desorbs semi-volatile substances. The enriched gas stream is then fed into the mass spectrometer where the absorbed substances can be precisely analysed, they stated.
"One particular strength of our approach is that even the surfaces of living organisms can be examined," he stated. "It only takes a few seconds to measure a single sample, so large numbers of random samples can be routinely analysed."
For meat samples the scientists were also able to show that the sample material does not even need to be thawed.
"In view of the numerous possible applications, it is not surprising that the new method is of interest not only to foodstuffs technologists and safety experts but also to medical professionals and drugs investigators in sport," Zenobi stated.

Ver mas: Journal Angewandte Chemie

Aoporte de: Guillermo Figueroa