Keywords: authentication, counterfeit fertiliser, DNA, supply chain security, tagging, traceability.
Counterfeit fertiliser is a global issue, with blind tests regularly highlighting the high proportion of substandard product on sale to farmers, particularly in poorer countries. Fake fertilisers cost the world’s economy billions of dollars a year; reduce crop yields and may even contain toxic materials which are harmful to human health. The nature of fertilisers means that it is extremely difficult to differentiate between counterfeit and genuine products without extensive laboratory testing. This paper will consider the use of synthetic deoxyribonucleic acid (DNA) molecular tags to ‘label’ the fertilisers themselves, as well as to secure printed batch information on outer packaging. The SigNature® DNA tags used in this case study can be authenticated in the field using portable testing equipment, providing forensic traceability throughout the supply chain.
In this example a unique DNA tag was added to granular fertiliser in the coating drum. Homogeneity testing showed that this provided a consistent method of application, with the level of DNA recovery closely correlated with the amount of coating added to the drum. This uniform tagging performance enabled dilution of fertiliser with untagged granules to be successfully detected. Analysis also confirmed the DNA was extremely stable on fertiliser for a period of at least 12 months at elevated temperatures (60°C).
A case study demonstrating the practical use of DNA tagged fertiliser is presented. This follows the full-scale production of 3,000 metric tonnes of granular fertiliser in Europe through to a final destination in Ghana where in field authentication of the SigNature DNA tag confirmed the fertiliser to be a genuine product. This successful trial established the applicability and usefulness of DNA tagging to enhance traceability throughout the global fertiliser supply chain.