Can we use LC-MS/MS for Horse Meat Detection?
Blog Nov 22, 2013
Following the Food Standards Agency’s (FSA) announcement in January that horse and pig DNA had been identified in beef products sold by several supermarket chains, further testing across Europe and beyond has revealed widespread incidences of such contamination.
In response AB SCIEX presented an LC-MS/MS-based method that offers an accurate and reliable approach to meat speciation. We caught up with Ashley Sage, Senior Marketing Manager at AB SCIEX, to understand more about this development.
AB: What techniques are currently employed for horse meat detection and what are their limitations?
Ashley Sage (AS): Currently, meat speciation/adulteration is done by detecting the DNA of a specific species. This is typically done using qPCR (quantitative polymerase chain reaction) whereby the DNA of a particular species is amplified and thus detected. Typical detection criteria allow 1% horsemeat DNA to be detected in relation to other species' DNA. The process takes somewhere from 30 mins to typically 2hrs to complete and is generally highly sensitive, but its limitations include concerns around the selectivity of DNA-based detection. For example, if horse hair were to accidently get into a production line of processed beef, PCR would result in a positive result for horse detection in the sample, because it measures DNA from the hair rather than the protein from the meat.
Other techniques such as ELISA can be used for screening purposes but these may result in cross reactivity with other species, also giving false positive results.
AB: What benefits does LC-MS/MS offer over these techniques?
AS: LC-MS/MS offers the capability to be more selective for the exact species, by measuring marker peptides from a specific animal's protein. By measuring the unique peptide derived from the protein of a species, you are confirming the exact presence and eliminating the opportunity to get false positives. One other plus point with LC-MS/MS is that the analysis can be multiplexed, allowing several species to be detected simultaneously, including banned substances such as steroids and antibiotics that are often given to animals.
AB: How does the sensitivity and selectivity of LC-MS/MS compare to PCR and ELISA?
AS: The sensitivity of the LC-MS/MS method compares extremely well with the other techniques. The method that AB SCIEX has developed can clearly detect horsemeat down to the 1% level in beef for example. More recent advances by the AB SCIEX team and our collaborators have resulted in better detection by LC-MS/MS and these data will be published soon.
AB: What has been the reaction to this work in the food testing industry?
AS: LC-MS/MS analysis has become a routine technique in the food testing industry over the years and we are seeing more interest from people who want to introduce it for the first time to their labs. With the gains you get by using LC-MS/MS, such as high sensitivity, high selectivity and the ability to multiplex assays across several species, whether it be meat speciation or other types of analysis such as allergen detection, the use of LC-MS/MS technology will continue to grow.
AB: Do you expect to see uptake from labs and a transition from current techniques?
AS: We hope so!