Song Liang Contributes Expertise on Foodborne Parasites to United Nations Report

Professor and Chair of Environmental Health Sciences Song Liang recently participated in a scientific meeting of the Food and Agriculture Organization (FAO) of the United Nations to address the global challenge of parasitic contamination in food.

Approximately 30% of foodborne illnesses globally are caused by parasitic infections, with protozoan parasites such as Cryptosporidium, Giardia and Toxoplasma gondii among the most significant. These pathogens are commonly transmitted through contaminated water, undercooked meat or fresh produce. They can cause serious gastrointestinal illness worldwide, particularly in young children, pregnant people and those with weakened immune systems.

To address these challenges, FAO convened an expert meeting in late May at its headquarters in Rome, Italy. The meeting focused on reviewing the latest scientific evidence and assessing the current state of detection, prevention, and control measures of foodborne protozoan parasites.

An executive summary of the meeting provides these takeaways:

• Education, training and capacity building on foodborne protozoan parasites should be recognized as a priority and should be approached using a One Health framework.
• High-risk foods include fresh produce, shellfish, dairy, juices and ready-to-eat items, where parasites resist harsh conditions and even low doses can cause illness.
• Vulnerable groups, like young children, pregnant people, travelers and immunocompromised individuals, are most likely to fall ill and endure chronic complications. Human nutritional deficiency also greatly influences both the severity of infection and clinical outcomes.
• Detection methods remain inconsistent, with few standardized testing methods across food types. Advances in molecular tools show promise, but reliable viability assays are scarce. Improved surveillance methods are needed.
• Control depends on hygiene and processing, including safe water use, thermal treatments, and innovative interventions, while recognizing that raw‐food preferences limit some options.

Liang's research interests lie in the intersections of environmental epidemiology, ecology and transmission modeling of water and vector-borne diseases, as well as the impacts of climate change on health. His team adopts collaborative and interdisciplinary approaches, combining field and laboratory investigations with systems modeling, all grounded in the One Health framework.

Liang's work has received support from various federal and international agencies, including the National Institutes of Health, National Science Foundation, the World Health Organization and the Bill & Melinda Gates Foundation.