Chocolate has a special place in many of our lives. It is widely seen as an affordable and essentially harmless treat – a food of comfort, celebration and joy. But those bars, cakes and Easter eggs are also part of a £61 billion (€72 billion) a year global industry with a troubling history of social and environmental harm.

For example, there are now an estimated two million child labourers working on cocoa farms in west Africa. Some are tricked or sold into slavery on those farms where they are forced to carry heavy loads of cocoa, use harmful pesticides, and handle machetes.

Reports suggest the problem is getting worse, despite promises from large chocolate producers. Multinational chocolate firm executives have admitted that the cocoa supply chain is “broken”.

The high demand for chocolate products and volatile price of cocoa means that some traders seek to buy cheaper beans from deforested regions and lower quality plants. This affects the prices and practices of legitimate farmers, reducing sustainability gains that have been made, such as improved land management.

At the heart of this complex issue is the difficulty of tracing cocoa from farms to the end product. The majority of the world’s crop – around 70% – is grown on small farms in remote areas of Ghana and Ivory Coast.

From those farms it is collected by small-scale traders and taken to larger facilities, where vast quantities are traded on international markets. With many different parties mixing crops early in the supply chain, tracing beans back to their farms of origin becomes extremely difficult.

So far, certification schemes such as Fairtrade, which aim to encourage responsible sourcing, appear to have failed. Some well-known chocolate brands such as KitKat have dropped ethical labels and self-certification has become increasingly popular with the likes of the company which owns Cadbury Dairy Milk.

But our research suggests a solution could now be within reach, with a reliable system that tracks the journey from cocoa trees to the chocolate in your fridge.

The system uses something called “biomarkers”, which are like biochemical fingerprints or bar codes extracted from the plant’s DNA. These provide a unique identifier of a plant that is also observed in its beans. The biomarkers in cocoa beans are so hardy they can even survive the industrial processes used in chocolate making.

Test and trace

This allows for the identification of an individual farm’s beans from a mixture of beans of different origins in the final product. The method has now been successfully tested in a study of cocoa supply chains, tracing specific plants on individual farms through to chocolate products.

If a database was created with sufficient samples, chocolate bought anywhere in the world could be traced back to the farm where the cocoa was originally sourced. Chocolate producers and customers would know precisely where the raw material of their chocolate has come from.

While the solution has proved to be effective in our small pilot study, if the method can be scaled up effectively, there can be no excuses for continued abuses within chocolate supply chains. Claims that farms are too widespread or remote, or the cocoa supply chain too complex, become empty.

Such a biomarker database identifying the origin of cocoa products could be built by firms or done independently at an estimated cost of around £5 per farm – the cost of a box of chocolates. The industry’s serious challenges of child labour, modern slavery, and environmental degradation could then be addressed, with targeted audits of specific farms where chocolate producers source their cocoa.

The chocolate industry and governments need to face this ethical challenge. We have developed an effective tool for them to make progress – and drastically improve a trade that is rife with environmental destruction and human misery.

This article originally appeared in The Conversation on 14 July 2021. Michael Rogerson is a PhD candidate at the University of Bath. Glenn Parry is professor of digital transformation at the University of Surrey. Pedro Lafargue is a research fellow at the University of the West of England.