Using DNA in Food Traceability

Today’s food industry is truly global, involving producers and manufacturers from around the world. Consumers are increasingly demanding transparency about food composition. However, ensuring traceability along the entire supply chain, from primary production to the end-consumer product, is challenging. The number of intermediaries and geographical locations involved in manufacturing processes creates a network that requires the most advanced traceability systems.

On the analytical side, food traceability remains a challenging topic. The aim of the traceability system is to guarantee the integrity of food from a raw material to a final product for the end consumer. Many methods have been proposed to track ingredient composition and identification along the supply chain. However, until now, very few methods have been identified that can really tackle this complex problem. These include DNA-based methods more focused on species identification and chemical methods, like stable isotopic analysis, which is a very powerful tool for origin and wild/farmed ingredient tracking.

Within food traceability, one of the hot topics is food authenticity to guarantee the correct composition of a product according to the description of that product and what is expected to be included in it.

Today we are seeing food authenticity being introduced to the routine testing and regulatory arena. Recent food fraud scandals mean it is imperative that the industry be able to identify the food ingredients that compose each food product, whether meat-, fish-, or plant-based. However, ready-to-eat products that are generally composed of several ingredients are more complex, particularly if those ingredients are sourced from different geographical origins, each with its own requirements. This means that the global food industry needs to adapt to the challenges presented by a dynamic and rapidly growing food market.

Popularity of NGS

The introduction of DNA-based tracing methods brings new and very powerful tools for identification of many ingredients in processed food products. One of the most recent DNA-based methods introduced for food analysis is next-generation sequencing (NGS). This method is dramatically changing the analytic approach, moving from the detection of one or a set of species to determining all species in a sample.

Currently, NGS is the only method that ensures the correct identification of species in complex foods. Its use by all major laboratories for food authenticity analysis is increasing.

The NGS method is based on DNA analysis through DNA sequencing and produces millions of individual DNA sequences all grouped in a single file. With NGS, different sequences can be produced from the various DNAs composing the food product. This means that the method is appropriate to use in products containing many ingredients visually not identifiable and mixed. Basically, since each different ingredient contains a unique DNA sequence (its own fingerprint), NGS will virtually sequence each one of the DNA molecules present in a sample to produce individual DNA sequences for each. Therefore, unlike the Sanger DNA sequencing method that originates only one DNA sequence from a food sample, NGS is the method of choice for DNA sequencing identification of products containing multiple ingredients.

Using appropriate software, the scope of NGS is virtually unlimited and it can be used on any kind of sample DNA, whether it contains different DNA sequences or not. This means that any kind of species can be detected, as the analytical method is no longer focused on detection of a limited number of species. Despite different NGS platforms available in the market (Illumina, Thermo Fisher Scientific, Pacific Biosciences, Oxford Nanopore Technologies), all of them are used to obtain sequences of defined regions in the DNA molecules and produce huge text files containing millions of individual sequences.