Authenticity testing is utilized to prove the content of food products is authentic and the way they are presented is correct and accurate. Food fraud covers intentional alterations made to the content of food products for economic gain. This not only undermines food authenticity, but the presence of toxic or undeclared adulterants may put consumer’s health at risk.
Figure: common adulterated products from IFT
There are two different approaches to food authenticity testing, depending on the type of fraud and level of vulnerability: targeted and non-targeted analysis. Targeted analysis is used when the adulterants are known, or the food in question has naturally built in markers.
Targeted Analyses are used if the adulterating materials are known or if the authentic food contains specific marker compounds. The range of technologies used for targeted testing is quite broad, covering everything from traditional wet chemistry, chromatography and mass spectrometry methods to molecular biology like qPCR and Next Generation Sequencing (NGS). An emerging technology to protect consumers against food fraud is NGS. As the identification of the species present in food and feed samples is a critical step in food production, the company’s solutions provide proof of authenticity, verification of origin, traceability of raw materials and quality control in food handling and processing. This enables food laboratories to identify the plant, fish and meat species contained in the most complex food samples.
Non-Targeted Analyses (NTA) have been growing in popularity as a result of measuring technologies and data analytics have advanced. The entire profile or specific characteristics of a food or feed sample are determined as a molecular fingerprint which will be compared with other reference data from a previously created database. If the new profile image matches the reference profile stored in the database, the sample is authentic.
These fingerprints are obtained using a variety of technologies, chosen based on the food and attributes being fingerprinted. For large molecules, instruments such as MALDI-TOF can obtain information on the molecular profiles in the foods. For smaller molecules, nuclear magnetic resonance (NMR), spectroscopic (such as IR, NIR, Raman) Liquid chromatography with assorted detection methods, including high resolution mass spectrometry MS/MS and QTOF are also being developed.
The most common molecular method to verify species substitution and species identification is real-time PCR. However, PCR testing is limited by the number of targets that can be simultaneously identified and differentiated and requires knowledge about which species to search for. This can be critical, especially when testing highly processed and complex foods that often contain multiple different species.
The introduction of Next Generation Sequencing (NGS) into the food sector revolutionizes food authenticity testing. An NGS untargeted approach enables accurate detection and differentiation of thousands of different species in each sample using DNA sequencing which is recognized as the most reliable method for species identification. At the end of an NGS analysis, millions of individual sequences are obtained making it possible to identify species in complex foods containing multiple ingredients. This is because each DNA-containing ingredient will produce a single and unique DNA sequence. The sequences obtained can be compared against a database resulting in a complete list of all the species present in the sample.