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Food safety advice for people who are at an increased risk of infection

Patient information A-Z

It is especially important to follow food safety guidelines when your immune system is weakened. Germs and toxins (which are poisons made by the germs) can be passed to you by food that has been incorrectly stored, handled and cooked. This could result in food poisoning.

Food poisoning symptoms include fever, cramps and headaches as well as nausea, vomiting and diarrhoea. You should seek medical attention if you suspect you have food poisoning.

A primary reason for cooking food is to destroy germs. Those with weakened immune systems should be aware of their increased risk from raw or insufficiently cooked foods.


  • Buy food as fresh as possible.
  • Check any ‘best before dates’.
  • Keep the food cool if you are not going straight home.
  • Carry a cool box and use it for perishable items. Do not put food directly into a hot car.
  • If you intend freezing any items such as meat or fish, do so as soon as possible. Do not store it for a couple of days before freezing it.
  • Do not buy improperly commercial-canned or home-canned or preserved foods.


Buy a special food storage thermometer from a supermarket or freezer store. Use it to check the temperature of your fridge and freezer at least once a week.

  • Your fridge should be between 2oC and 4oC.

Your freezer should be at or below minus 18oC.

  • Raw meats and fish should be stored on a lower shelf than cooked foods. This will avoid drips contaminating food that is ready to eat.
  • Cook meat or fish within two days or freeze it on the day of purchase.
  • Store eggs in the main part of the fridge because this is at a lower temperature than the door racks.
  • If you do not use much cooking oil keeping it in the fridge may stop it going rancid.
  • Keep your fridge clean.
  • Make sure you wash your hands before preparing food.
  • Keep your kitchen as clean as possible.
  • Use an anti-bacterial cleaner for surfaces and equipment.
  • If any part of a piece of food has gone mouldy throw out the entire piece. Toxins can travel into the ‘good’ parts and poison them as well.
  • Marinade food in the fridge and not at room temperature.
  • Chopping boards are particularly dangerous as bugs or germs can hide in scratches and cracks. Use plastic boards and change them regularly.
  • Keep one board for raw meat and fish and another for fruit and vegetables.
  • Immediately after handling raw meat or fish wash your hands and any knives or chopping boards in hot water.
  • Use a hand towel to dry your hands, not the tea towel.
  • Wash fruit, salad and vegetables before eating.
  • Keep pets away from food and work surfaces.


  • Shellfish and steamed fish must be cooked for at least seven minutes.
  • Meat should be too hot to touch. If you enjoy roast meat it would be worth buying a meat thermometer to make sure that the centre of a joint reaches between 70oC and 85oC.
  • Cook eggs thoroughly and make sure both the white and the yolk are hard.
  • Cook boiled or fried rice according to the instructions and eat it immediately.
  • Barbecued food is a common source of food poisoning.
  • Make sure everything is well cooked in the middle.
  • Do not mix raw and cooked meats on the same plate


  • Allow food to cool, wrap well and store in the fridge.
  • Plastic boxes with well fitting lids are ideal for storage, or otherwise use foil or clingfilm.
  • Do not store cooked rice to reheat.
  • Eat leftovers within two days.
  • Reheat the food thoroughly. It should be at least 70oC in the middle.
  • Remember microwaved food is hotter at the edges!
  • Do not reheat cooked food more than once.

Other facts you should know

  • Beware of shellfish unless it has been steamed for at least seven minutes. (Most restaurants only cook shellfish for two to three minutes; this is not long enough to kill any germs they may contain).
  • Avoid sushi dishes with raw fish.
  • Do not eat dairy products containing raw (unpasteurised) milk. Check the label or ask.
  • Be especially careful to check labels of soft ripened cheeses, for example, Brie and Camembert, also some cheeses made from goats’ milk.
  • Blue cheeses should be avoided. All cheese is safe when well cooked.
  • Meat pastes and pâtés are best avoided unless well cooked and freshly prepared.
  • Avoid cold rice served in salad dishes.
  • Keep clear of foods with raw or lightly cooked eggs such as home-made mayonnaise, Caesar salad dressing or Hollandaise sauce, tiramisu, ‘luxury’ ice creams and mousses.
  • If any of your favourite dishes are listed then consider alternatives. For example: most mayonnaise purchased in jars will be made from pasteurised eggs.
  • Avoid grubby places!
  • Ask for your meat, fish or poultry to be well cooked or medium well done.
  • When your food arrives check that is well cooked and hot. You are the customer!
  • Make sure that all foods which are supposed to be cold are chilled and not at room temperature.
  • Be careful about selecting food from salad bars. Check that the food is cool and fresh.
  • Food containing lightly cooked eggs can be tricky. Ask if the restaurant uses pasteurised eggs.

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Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

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Cambridge University Hospitals
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Hills Road, Cambridge

Telephone +44 (0)1223 245151