When cooler weather arrives in Aotearoa, kai becomes one of our favourite comfort blankets. Cooking dinner for a hungry whānau is a small reminder of how much trust we place in our food.
During Food Safety Week, PHF Science is taking a closer look at one of the foodborne threats we watch closely: STEC. It is not something most people want to think about at the dinner table but understanding it helps keep people safe.
STEC is short for Shiga toxin producing Escherichia coli. It is a mouthful of a name for a foodborne pathogen that can mean a long miserable week with stomach cramps and diarrhoea, sometimes bloody, but can also lead to severe disease and kidney failure, especially for young mokopuna.
For PHF Science senior scientist Jackie Wright, STEC has been a part of her research for more than three decades. In 1993, she made the first case report of E. coli O157:H7 (STEC) in Aotearoa, a common cause of outbreaks worldwide. Jackie’s discovery helped launch critical national surveillance that laid the foundations for the public health response we rely on today.
Over time, PHF scientists and partners recognised that STEC was not a rare oddity. It is a significant disease in our community, requiring close monitoring to understand how it spreads and how we can limit its impact.
Technological advances
A major advance began in 2017, when PHF Science started transitioning STEC epidemiological typing to whole-genome sequencing. Jackie returned to PHF Science to lead the Enteric Reference Laboratory through the shift, working alongside laboratory teams, bioinformaticians and colleagues in health information and surveillance. Whole-genome sequencing lets researchers compare STEC strains in fine detail, helping identify which cases are likely linked and supporting investigations into possible sources of infection. As diagnostic laboratories adopted newer testing methods, more STEC infections were being detected, including strains beyond the best known O157.
In 2025, Jackie and colleagues published a major national analysis of STEC illness in Aotearoa covering the years 2016 to 2022. The study reported a substantial burden of illness, with 5,769 confirmed STEC cases over seven years. Many infections appeared sporadic, which can make the source of illness harder to identify. That is why ongoing surveillance, robust laboratory methods and careful analysis remain so important.
To further reduce harm, scientists also need to understand not only what STEC is, but how it travels. This is why STEC research increasingly draws on One Health, an integrated approach recognising that the health of humans, domestic and wild animals, plants, and the wider environment are closely linked and interdependent. Jackie led a recently completed New Zealand Food Safety Science and Research Centre (NZFSSRC) funded comparative genomics study that compared STEC from human, animal and environmental sources across Aotearoa. The project is a powerful step in bringing together collaborators from the Bioeconomy Science Institute, Massey University and PHF Science to pinpoint transmission pathways and stop infections before they happen.
PHF Science senior scientist Ernest Williams now leads the whole-genome sequencing of STEC clinical isolates in the PHF Science Enteric Reference Laboratory. Ernest recently represented New Zealand on a global panel discussion around health security, genomics and data sharing in a global economy.
“Strong partnerships between the food industry, scientists and regulatory agencies, will help ensure food safety and quality go hand in hand for the benefit of Aotearoa and our trade partners”, says Ernest.
Keeping food safe
PHF Science’s advanced analysis methods help us better understand which STEC strains are circulating and causing harm in our communities and support faster public health responses during outbreak investigations. At home, a few simple steps can help protect your whānau.
- Wash your hands well with soap and water, especially after handling livestock, domestic pets, or raw meat; using the toilet or changing nappies.
- Keep raw meat away from ready to eat foods. Use separate boards or plates to stop cross contamination.
- Cook minced meat and sausages until they are piping hot and the juices run clear.
- Take time to wash your fruit and vegetables.
- Refrigerate leftovers promptly and keep cold foods cold, especially when packing lunches or taking food to gatherings.
For all of us enjoying slow cooked meals bubbling away on the stove, it is reassuring to know there are expert teams working quietly in the background to understand different risks to food and reduce disease harm.
See New Zealand Food Safety’s website for up-to-date food safety information.