The wide use of meat products, particularly when minced or ground into products such as sausages, burgers, meatballs, meat fillings and other products, has the potential to leave room for adulteration of these products to occur.
As consumers are becoming increasingly aware of the possible contaminants that can enter their food supplies, government agencies such as the United States’ Food and Drug Administration (FDA) are required to maintain strict regulations of what is acceptable for human distribution.
To address this concern, group of researchers from the University of British Columbia in Vancouver, Canada have utilized Fourier transformed-infrared (FT-IR) spectroscopy as a highly sensitive technique to detect such alterations in meat products.
Limitations of Current Detection Assays
In January of 2013, the Food Safety Authority of Ireland analyzed 27 hamburger products labeled as containing “100% beef,” only to discover that 10 out of those tested positive for horse DNA and 23 positive for pig DNA1.
A number of companies with distribution centers across Europe were affected by this discovery, thereby leading to an increased concern over the integrity of such beef and other meat products in other areas of the world.
The substitution of beef and pork by the cheaper and less-consumed meat parts of other animal species, as well as by byproducts of the same species of animals, is a deliberate action that companies can take for their own selfish economic gains.
Current analytical techniques that are used to test for the authenticity of meat products are based upon the quantification of protein or DNA concentrations of the product to differentiate whether these measurements are of the same or different biological species.
One major limitation of assays like DNA barcoding is that it is unable to detect different types of meat cuts that originate from the same species, thereby leaving room for products to be deliberately contaminated with animal offal.
Adulteration Detection by FT-IR Spectroscopy
Until this study was published in Nature, no previous research studies have been capable of applying spectroscopic techniques to identify offal in beef meat samples.
As the first study to identify beef offal adulterants, such as liver, omasum and tripe, as well as pork offal including heart, kidney and liver components, the researchers purchased three different types of beef cut, pork cut and offal for each animal type.
For this study, the spectrometer was coupled with a Horizontal Attenuated Total Reflectance (HATR), which allowed the meat samples to be examined directly in the solid state by a beam of infrared light.
Once the researchers adulterated the meat samples, they were then deposited directly onto the HATR ZnSe crystal sensor of the FT-mid-IR spectrometer for chemometric analysis. To adequately interpret the variances presented by the analysis, principle component analysis (PCA) was also used to differentiate the produced spectral data into two parts of actual observations, or “structure,” and spectral variables, or “noise.” PCA is a useful technique that allowed the researchers to recognize any patterns or outliers in the data to adequately score the pure beef/pork samples as compared to those that contained offal parts.
The protocol devised by these researchers was successful in not only differentiating authentic beef meat samples from those that were adulterated with one of the six types of offal, but also to identify the specific type of adulterant that was incorporated into the beef sample in a highly accurate manner.
With potential applications for future governmental laboratory and food industry purposes, the researchers are hopeful that the utilization of this analytical technique could strengthen the meat products that are offered by the market.
“What’s behind the horsemeat contamination scandal?” – CNN News
“Detection and quantification of offal content in ground beef meat using vibrational spectroscopic-based chemometric analysis”Y. Hu, L. Zou, et al. Nature. (2017). DOI: 10.1038/s41598=017-15389-3.