Around the world, food safety systems help protect billions of people every day, but ongoing research is essential to ensure those protections keep pace with changing risks. Understanding how much illness unsafe food causes is critical for governments and industries deciding where to focus food safety resources. Without reliable data, it is difficult to know which risks matter most, whether control measures are working, or how foodborne threats are changing over time.
That challenge sparked one of the most ambitious public health projects ever undertaken.
Counting the global burden of foodborne disease
In 2007, the World Health Organization (WHO) brought together more than 100 international experts to answer a complex question: what is the true global burden of foodborne disease?
Among those contributing to the project was PHF Science’s Rob Lake, who volunteered his expertise as part of the international collaboration. The task took years of scientific work, bringing together data from around the world to estimate how many people become ill, disabled or die from contaminated food each year.
Published in 2015, the first global estimates revealed the enormous scale of the problem. WHO estimated that 31 hazards in unsafe food cause roughly one in 10 people to become sick each year. Researchers also expressed the burden of illness and premature death using a combined measure known as “disability adjusted life years (DALYs)”. Foodborne disease was estimated to cost the world 33 million years of healthy life lost annually. The findings became a landmark moment for global food safety, giving policymakers and regulators the first global picture of the human cost of unsafe food.
The next generation of estimates
Food safety risks don’t stay static. Climate change, evolving food systems, changing diets, global trade and population growth all influence how foodborne diseases spread and who’s most at risk. To understand whether food safety interventions are working, and where new risks are emerging, the burden estimates need to be updated regularly. Recognising this, WHO launched the second global burden of foodborne disease study in 2021.
For the past five years, PHF Science’s Dr Rob Lake has chaired the core group of international experts responsible for supporting WHO to deliver the 2026 edition of the estimates: the Foodborne Disease Burden Epidemiology Reference Group (FERG). The work involves seven specialised task groups, over 20 commissioned systematic reviews, data collection across 194 countries, and analysis of illnesses and deaths linked to 42 biological and chemical hazards.
Each country has different disease surveillance systems, reporting standards and levels of available data, making the work highly complex. Every dataset, calculation and scientific conclusion must also undergo rigorous checking to ensure the final estimates can be published with confidence.
A global focus on food safety
World Food Safety Day, on 7 June, is an annual WHO campaign highlighting the importance of safe food for health, trade and sustainable development. Immediately prior to this, on 4 June, WHO launched the updated estimates.
For the year 2021, the WHO estimated that 42 hazards in unsafe food cause around 866 million illnesses, 1.5 million deaths, and 57 million DALYs across the world. This DALY burden is comparable with diseases such a tuberculosis and malaria. The total is built up from estimates for all individual countries.
These estimates will support risk-based decision-making, strengthen national food control systems, and provide tools to monitor the prevention of foodborne diseases globally.
For PHF Science, the project reflects New Zealand’s ongoing contribution to global food safety science, and the critical role robust evidence plays in protecting public health.