The liquid chromatography and tandem mass spectrometry (LC/MS/MS) based method allows food laboratories to detect a number of biomarker peptides that are specific to pig and/or horse.
For Muslim and Jewish communities it is critical to know about contamination of foods that are considered permissible to eat (‘halal’ and ‘kosher’), having been prepared in accordance with Islamic or Jewish beliefs, respectively.
To help serve these communities that make up 23% of the global population, scientists at the German university and AB Sciex developed a way to detect contamination of meat, including beef, chicken, lamb and others.
“Scientists in routine testing laboratories worldwide will now be able to use this method to detect and distinguish trace amounts of pig and horse in many food products,” said Prof. Dr. Hans-Ulrich Humpf, head of the Institut für Lebensmittelchemie [Institute for Food Chemistry], University of Münster.
Versus traditional methods
The mass spectrometry-based method can detect markers of multiple, different animal species in a single run vs. traditional methods, such as polymerase chain reaction (PCR) or enzyme-linked immunosorbent assay (ELISA).
PCR and ELISA are older, widely-used approaches which detect the animal’s DNA or intact animal proteins, respectively, but both have limitations such as their lack of specificity, which can lead to false negative or false positive findings.
Species authentification is an important quality control parameter for meat products because the fraudulent substitution with meat from lower priced species drastically increases the profit margin, said the developers, who used prices for beef as about twice as high as those for pork.
The method was developed with a two-pronged LC/MS/MS approach, using the TripleTOF 5600 system to identify the unique protein markers specific to a meat species, then the QTRAP 5500 system to detect and confirm the presence of targeted meat peptides in unknown samples.
QTRAP 5500 system uses multiple reaction monitoring (MRM) to detect each peptide and can then provide sequence information by acquiring a product ion scan for each triggered MRM, which can be used to confirm the peptide’s identity.
Horse and beef protein markers can differ by as little as one or two amino acids, so it is important to have confidence in the results when distinguishing between species.
The method presents the first MRM and MRM3 method for detection of both species (down to 0.13-0.25%), using routinely available MS techniques.
“One of our goals was to develop a method that could be widely and routinely used by scientists in food testing labs, many of which have suitable mass spectrometry platforms,” said Dr Jens Brockmeyer, research group leader at the Institut für Lebensmittelchemie, University of Münster.
AB Sciex has previously developed methods for protein screening, including techniques for detecting allergens such as eggs, milk, sesame seeds, nuts and mustard simultaneously in food samples.
Scientists at the firm are continuing to look into other similar areas of ethical concern, including detection of gelatin that has come from species such as beef and pork.
Source: Journal of Agricultural and Food Chemistry, 2013, 61(49), pp 11986–11994
Online ahead of print. DOI: 10.1021/jf404121b
“New Sensitive High-Performance Liquid Chromatography–Tandem Mass Spectrometry Method for the Detection of Horse and Pork in Halal Beef”