Pioneering DNA and mass spectrometry tests for the detection of almond and mahaleb further developed by the Government Chemist programme
Scientists working within the Government Chemist programme have made further developments in DNA testing that, along with mass spectrometry, are able to distinguish between almond and mahaleb.
Following work on cumin a sample of paprika was referred to the Government Chemist by the Food Standards Agency after it appeared that almond, a species known to be an allergy risk for some individuals, was present in the sample. It is understood that the product did not enter the UK food chain.
Almond is a member of the genus ‘Prunus’ - trees and shrubs, which includes the plums, cherries, peaches, nectarines, apricots and mahaleb. Prunus mahaleb, previously little known in the UK, was responsible for false positive results for almond in cumin. The Government Chemist was asked if it is possible to tell whether almond or mahaleb or both is present in the referred sample of paprika. This required further investigation of the analytical methods previously developed for cumin to ensure they are applicable in paprika.
ELISA , the most commonly applied technique for the detection of food allergens, reacts to several common Prunus species, as do some PCR DNA assays. To our knowledge there is no available DNA assay that appears specific to almond only.
In order to investigate the issue, a multidisciplinary team of LGC scientists applied ELISA and advanced DNA and mass spectrometry techniques. The team confirmed that the referred sample contains Prunus species proteins. Specially developed DNA tests showed that mahaleb DNA was not present but a profile for the sample consistent with the presence of almond DNA was found. This was confirmed by chromatographic and mass spectrometric data.
Although limitations still remain in the state of the science, the referred sample contains Prunus protein(s) and DNA the origin of which is consistent with almond rather than mahaleb. Michael Walker, consultant referee analyst, said:
“ELISA detection is useful in screening for the authenticity of spices and thanks to the expertise in molecular biology and protein mass spectrometry in LGC we have further developed our ability to distinguish almond and mahaleb in spices.”
The techniques developed in the above research will be submitted to peer reviewed scientific journals for publication.
The Government Chemist is grateful to the Department for Business, Innovation and Skills and to the Food Standards Agency for funding the above study.
Published: 12 November 2015
From: Government Chemist