Science of Chocolate

Dark, delicious and decadent, the rich flavour of chocolate has inspired passions, addictions and even literature for more than three thousand years. How much longer can we hope to enjoy plentiful supplies of chocolate? Professor David Guest, from the School of Life and Environmental Sciences, is helping counter a chocolate catastrophe.

Cacao is produced from fruit of the tropical tree, Theobroma cacao, literally meaning 'food of the Gods'. Not just appetising, chocolate also has health benefits – including reducing blood pressure and enhancing psychological happiness.

As cacao is grown in areas vulnerable to threats of climate change, political instability, poverty and poor health, pests and diseases, Professor Guest will focus on the major threats to our chocolate supply.

"We're in a situation where chocolate manufacturers are anxious about meeting demand, as there's rapidly increasing chocolate consumption in developing economies, paired with instability in cacao growing areas," said Professor Guest.

"Threats to cacao production include pests and disease, ageing plantations, poorly trained farmers and poorly managed trees, poverty and human health problems, climate change, dependence on a narrow genetic base, and easier crops to grow, such as oil palm and maize."

To counter a chocolate catastrophe, Professor David Guest's research supports the chocolate industry by improving the sustainability and profitability of smallholder cacao production. Professor Guest and his colleagues' work with farmers in Indonesia, Papua New Guinea and Bougainville shows that improved rural health supports good farm management that increases yields, resulting in improved living standards, reduced rainforest clearing, political and social stability, and securing future supplies of chocolate.

"We work with farmers to select better genotypes of cacao, to demonstrate improved crop and soil management, to understand the constraints they face and what can be done to improve technical support," said Professor Guest.

"The keys to reducing diseases and pests are sanitation, pruning and regular harvesting. We have a mantra for the farmers to remind them to regularly harvest their cacao crops: 'Every pod, every tree, every week'.

"We've found it's really effective to explain to farmers that disease is caused by microorganisms similar to those that cause human disease. Showing farmers how the pathogens survive and spread helps their understanding and leads them to realise that they can reduce disease with improved management. Improved management does require extra work, so working with our colleagues in community health and nutrition is important to improve the productivity and stamina of farmers," explained Professor Guest.

"Otherwise cacao farmers tend to blame nebulous factors like climate change or more virulent pathogen strains, which they feel powerless to do anything about. This powerlessness is compounded if they suffer from disease or malnutrition."

The chocolate crisis is exacerbated by the fact that global chocolate consumption is rising by 2-3% annually.

"Chocolate consumption trends are different around the globe. In Australia, Europe and North America total consumption – between 6 and 12kg of chocolate per capita per year – is stable, but the trend is to dark and niche marketed single-origin chocolates," said Professor Guest.

"In China, India, Eastern Europe and Brazil, however, per capita consumption rates are increasing rapidly, albeit from a very low base.

"The consensus is that global production will need to increase by one million tonnes per year by 2020 – from about 4 million tonnes currently – to meet global demand."

Circumventing a chocolate catastrophe is in capable hands.

"While controlling disease is relatively straightforward in theory, changing farming practice to become more sustainable and rewarding is a much more complex challenge involving social, economic, political and environmental factors, sometimes referred to as a ‘One-Health’ approach," said Professor Guest.

"This is a challenge we have to meet if we are going to secure the world's supply of chocolate, while at the same time improving the livelihoods of cocoa farmers."