Escherichia coli (STEC) infection: symptoms and advice

What types of E. coli cause illness?

E. coli (Escherichia coli) is a bacterium that normally lives in the intestines of people and other warm-blooded animals. Although most strains of E. coli are harmless, some types can make us sick. One of the harmful strains is known as Shiga toxin-producing E. coli (STEC), also called VTEC. We can get sick from eating food contaminated with it, and from other sources.

Symptoms of STEC illness

STEC infections usually cause:

mild or severe diarrhoea, which can be bloody
stomach cramps.

People usually get these symptoms 3 to 9 days after being infected.

Most people recover within 10 days. However, a small number of people can develop life-threatening conditions. There is a higher risk for these groups of people:

infants
the sick and frail
older people
people with low immunity.

One life-threatening condition is acute kidney disease. Most people completely recover from this but a few may go on to have chronic issues. While deaths occur, they are rare.

Food safety information for high-risk groups

Food safety advice for people with low immunity

Food and pregnancy

How you can get sick

People usually get sick from STEC through:

direct contact with contaminated farm animals, animal faeces, and farm soil
untreated water
eating contaminated food
contact with people who are sick with STEC and haven't washed their hands properly.

Food can get contaminated with STEC when the food comes into contact with farm animal faeces. Food hygiene practices are designed to prevent this from happening.

In other countries, people have gotten infected from eating contaminated:

raw or under-cooked minced meat products (like mince and sausages)
raw vegetables (mainly leafy greens and seed sprouts)
raw milk.

Under-cooked meat and vegetables have not been linked to STEC illness in New Zealand. However, under-cooked meat can still carry other germs that can make us sick.

How to lower your risk of getting sick

When preparing food and cooking meat:

wash leafy green salad vegetables before use
cook all minced meat products and sausages thoroughly, and don't eat under-cooked mince products
make sure that any meat is cooked throughout (not pink anywhere). If you have a meat thermometer, check that the internal temperature is higher than 70°C.

Always cover cooked and uncooked food (especially leftovers), even if it's in the fridge or cupboard. Put leftovers in the fridge within 2 hours, or freeze them.

Avoid drinking:

raw milk, unpasteurised dairy products, and unpasteurised juices
untreated, non-tank water at farms.

Practice good hygiene

You should:

wash your hands immediately after touching animals or handling foods like raw meat and raw milk
make sure you, and people around you, wash their hands carefully with soap after using the toilet to reduce the risk of spreading the disease
wash your hands after helping sick family members
keep surfaces and kitchen utensils clean, to help prevent germs from spreading.

Always wash your hands with soap and dry them carefully before touching food. This is especially important for children in higher-risk environments, like: