There is growing pressure for producers and retailers to determine the geographical origin of the foods they distribute and sell, in response to new regulations around the traceability of foodstuffs. To do this properly, we need new analytical tools to track and trace what we eat.
European rules demand full traceability for all foods imported into or exported from the European Union. How can this be achieved? I believe that a new technique, known as biological barcoding, will do the trick.
Micro-organisms are always present on the surface of our food and a good source of information about the origin of each product. Biological barcoding allows us to link the organisms we find on our foods to the geographical location of their production.
We've tested this out. A molecular technique using DNA profiling was used to detect the variation of the microbial community present on the surface of produce, including bacteria, yeasts and moulds. This method allowed us to analyse and identify complex DNA structures from all the bacteria, yeasts and fungi we found. All the micro-organisms are visualised on a gel and the band on the gel can be photographed, providing a fingerprint of the ecological origin.
This technique has been applied to fish from South Vietnam harvested in different aquaculture farms, during rainy and dry seasons, and can discriminate between the origins of different fruits from Africa, such as physalis fruits from Egypt and mandarins from Morocco.
When the profiles were identified by multivariate analysis, distinct microbial communities were detected. The band profiles of fish bacteria or fruit yeasts and fungi from different farms were specific for each location.
For fish harvested from different farms in Vietnam, when band profiles within the same location at different seasons were compared, we observed the same banding pattern for every season and the analytical technique could discriminate between farms. Some common bands were found to be stable throughout the year regardless of the season.
These microbiological bands can be used as markers for very specific locations and offer a sustainable tracing method that can be used by the whole European food industry. This method is fast: it usually takes fewer than 24 hours to prepare a microbial profile. The resulting "fingerprint" recorded on the gels provides a unique biological barcode for food, connecting the food to its place of production.
There's no better way to ensure that traceability standards and regulations are upheld than by the introduction of biological barcoding, which provides products with a unique reference point and makes it possible to trace accurately from store to source.
Dr Didier Montet is head of the food safety team at CIRAD, the Centre de Coopération Internationale en Recherche Agronomique pour le Développement
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