People with low immunity

If you have low immunity, you're more at risk of getting sick from microorganisms (bugs) in food than healthy people. Find out how to help protect yourself from illness and get tips for preparing and storing food safely.


What is low immunity?

Your immune system normally fights harmful microorganisms or bugs (called pathogens) that can make you sick. But illness, medications, a recent hospital stay, pregnancy, or being very young or frail can mean your immune system is not as strong as it should be.

This puts you at a higher risk of getting infections – including those carried by food – and may mean your illness is more serious.

Following the information on this page can help protect you from foodborne illness – or food poisoning – and infection when you have low immunity caused by illness or a medical condition. It covers:


Get specific advice for your condition

Talk to your doctor or dietitian about food safety – they may give you different advice based on your illness or medical condition.

If you are pregnant, or looking after a very young child, we have targeted advice to help keep you or your baby safe.

What causes low immunity?

Your immune system may be suppressed if you are:

  • suffering from illnesses like cancer, HIV/Aids or inflammatory bowel disease
  • taking certain medications, including immunosuppressive drugs
  • an older person with an ongoing (chronic) illness.

Refer to page 2 of our food safety guide for people with low immunity to learn more about the causes.

Download the food safety guide [PDF, 1.2 MB]

Safer foods for people with low immunity

Food is generally safe but can carry small numbers of bugs, such as bacteria, parasites, viruses and toxins. If food is handled incorrectly, these bugs can cause foodborne illnesses with symptoms such as stomach upset, nausea, vomiting or diarrhoea.

You can minimise your risk of catching a foodborne illness by:

  • knowing which foods are high risk and avoiding them
  • selecting safer foods
  • following food safety guidelines when preparing and storing food. This helps prevent pathogens growing in, or contaminating your food.

Foods that may pose a risk

Some types of foods may pose a greater risk than others, and need to be prepared carefully to minimise the growth of bugs.

Our pullout guide for people with low immunity has the full list of foods that are safe and tells you how to prepare at-risk foods.

Download the pullout guide [PDF, 784 KB]

Dairy products

Most dairy products in New Zealand are pasteurised. Pasteurisation is a heat treatment that kills pathogens in raw products, but these products can still become contaminated once opened.

Dairy foods that should be avoided when you have low immunity include raw and unpasteurised products, commercially prepared and unpackaged smoothies or shakes, and soft-serve ice cream.

Learn more about high-risk dairy products:

Vegetables, salads and fruits

Fresh fruits and some vegetables should always be well-washed and dried to remove pathogens that may be on the skin, particularly if eating raw. Fruits and vegetables that are difficult to clean thoroughly, such as sprouts and some herbs, should be avoided.

Meat, poultry, seafood and eggs

If you have low immunity, you should not eat raw or undercooked:

  • meat, including poultry
  • eggs
  • fish or shellfish.

These foods should only be eaten if cooked until piping hot (over 70 degrees Celsius).

Non-commercial wild foods, recreational catch, collect-your-own and farmkill

You need to take care when eating non-commercial foods, as they are not prepared according to the safety regulations that apply to commercial foods. Before eating, make sure you are confident these foods came from a safe environment and were handled correctly.

Water

Untreated water may be contaminated with the same pathogens as food, as well as cryptosporidium and giardia. If you have low immunity you can get very sick from drinking untreated water. Water swallowed while swimming can also make you sick.

Reduce your risk by:

  • using treated water (such as from a town water supply) for drinking and cooking
  • regularly changing water filter cartridges. Water filters may be contaminated, so if you aren't certain the filter is safe, don't drink the water. Don't store filtered water
  • boiling untreated water for at least a minute if using it to drink, make ice, brush your teeth, wash fruit or vegetables or cook. Untreated water includes water from roof tanks, wells, bores, lakes and streams
  • preparing for emergencies by storing treated or boiled water in clean large plastic bottles (not milk bottles) with tightly fitting screw lids. You can also buy plastic water storage containers. Store out of direct sunlight. Check water every few months and replace if it's cloudy, has signs of algal growth or has an off flavour.

Buying, handling and storing foods safely

Besides choosing safer foods, if you have low immunity you need to make sure you buy, store and prepare foods safely.

Restaurants and takeaways

When you eat out or buy takeaways, avoid the same high-risk foods you would at home.

Best choices

To minimise risk, choose restaurant and takeaway food that is:

  • well cooked and prepared just before it's served to you
  • served steaming hot.

Avoid eating food from buffets, smorgasbords, salad bars or street vendors, as risks are harder to manage.

Don't eat:

  • raw eggs or foods containing raw eggs (such as mayonnaise, hollandaise sauce, Caesar dressing, some desserts)
  • unwashed fruits and vegetables, raw sprouts and raw herbs
  • pre-prepared cold foods such as salads, unrefrigerated sandwiches or sushi
  • undercooked or raw meat, poultry or seafood
  • cold meats, pâté or cold, smoked fish
  • soft cheeses (unless cooked)
  • soft-serve ice cream.

Overseas travel

If you're travelling overseas, be aware that some countries have very high rates of foodborne illness, and water supplies may not be safe.

Before you go, get advice from your doctor or a travel health clinic. While you're away, take extra care in checking that food and water (including ice) are safe.

Find out more

Our food safety guide for people with low immunity includes information on safe and at-risk foods, and gives advice on buying, preparing and storing foods.

Who to contact

If you have questions about information on this page, email info@mpi.govt.nz.

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