Making imported frozen berries safe to eat

Imported frozen berries can carry bacteria and viruses. Learn how to make sure the frozen berries you eat are safe.

How berries become unsafe to eat

Some berries can carry harmful bugs, like:

  • hepatitis A virus
  • norovirus
  • Shiga toxin-producing E. coli (STEC)
  • Salmonella.

New Zealand's food safety rules keep berries grown here safe to eat. But not all countries have the same rules. Berries grown and processed overseas can be unsafe to eat.

Harmful bugs can come from the farm where berries are grown. Sources can include:

  • unclean water or soil
  • infected workers and animals.

Food handlers, machines, and equipment can contaminate berries after they are harvested. The bugs can be spread during freezing, mixing, or packaging. This can make the berries unsafe to eat.

Making berries safe to eat

You can make frozen berries safe to eat by either:

  • bringing them to the boil, or
  • cooking them at 85 degrees Celsius for at least 1 minute.

Washing frozen berries will not remove the risk.

Most viruses and bacteria found on frozen berries can survive freezing. They also can survive freeze-drying, and heat treatments of less than 85 degrees Celsius.

Preparing berries safely is important when you:

  • make uncooked foods that normally contain frozen berries, like smoothies and desserts
  • serve berries to people with health risks.

People with health risks include:

  • older people, especially those with underlying health conditions
  • young children
  • pregnant women
  • people with low immunity.

Find out about food for people with low immunity

Disease outbreaks related to imported frozen berries

In 2015, New Zealand had an outbreak of hepatitis A. It was linked to people eating imported frozen berries.

Australia, the United States of America, and Europe have also had outbreaks of hepatitis A associated with frozen berries.

Outbreaks of norovirus infection have also been reported.

These outbreaks show that there is an ongoing risk in the global frozen berry supply chain.

Find out more

Hepatitis A virus fact sheet [PDF, 203 KB]

Hepatitis A disease – Ministry of Health

Norovirus – Ministry of Health

Who to contact

If you have questions about the risks of imported frozen berries, email info@mpi.govt.nz

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