Listeriosis prevention pack

Alemtuzumab Safety Advice: Listeriosis prevention

  • How to prevent listeriosis before, during and after treatment.

What’s the risk?

  • Your immune cells are dramatically reduced when taking alemtuzumab. Until the immune system recovers you have a greater risk of contracting infections through food, such as listeriosis. This could lead to septicaemia and meningitis.
  • The average time for the immune system to recover is 3 months.

What can I do?

  • A week before you start alemtuzumab treatment, follow all these guidelines. This will reduce your risk of contracting listeriosis through food.
  • Avoid high-risk foods:

    • Buffets
    • Pre-prepared salads
    • Ready-to-eat seafood (e.g. smoked fish) and raw seafood (e.g. some sushi)
    • Precooked meat products (e.g. pate, sliced meat)
    • Pre-prepared fruit or vegetable drinks unless pateurised or canned
    • Unpasteurised milk or any foods made from it (pasteurisation is the only way to destroy bacteria)
    • Ice-cream made from raw milk
    • Ice-cream if not served straight from the freezer (e.g. soft ice-cream from ice-cream vans)
    • Unpasteurised soft cheese (e.g. brie, Camembert) unless cooked thoroughly and served hot
    • Ready-to-eat foods stored for longer than one day in the refrigerator
    • Raw vegetables unless made yourself with thoroughly-washed vegetables
  • Eat safe foods:

    • Freshly prepared and cooked foods to be eaten immediately
    • Hard cheeses, cheese spreads and processed cheeses
    • Freshly pasteurised or UHT milk and yoghurt
    • Tinned and pickled food
    • Vegetables and salads you have washed and prepared yourself
  • Prepare food safely:

    • Stick to use-by dates
    • Keep your kitchen clean
    • Wash, peel, then rewash all raw vegetables, salads and fruits before eating
    • Thoroughly cook all animal-origin foods, including eggs
    • Ensure reheated food reaches at least 70C all the way through
    • Ensure food is evenly and thoroughly heated when using microwaves
  • Store food correctly:

    • Keep food covered
    • Refrigerate all cooked food within one hour
    • Consume food within a day of opening
    • Put stickers on your food to remind you when you opened/cooked it
    • Check your fridge is below 5C and recheck once a week [or month?]
    • Only defrost foods at the bottom of the fridge (to stop dripping)
    • Don't defrost food in the microwave or oven
    • Clean the inside of your fridge once a week with hot water and liquid soap, then rinse
  • Be careful when eating out:

    • Avoid buffet and street foods
    • Avoid salads and raw vegetable dishes
    • Avoid ice
    • Check food hygiene ratings at
    • Only eat food if it's served piping hot
    • Tell anyone cooking for you, or living with you, about these guidelines
    • Remember: it is ok to enquire about how food is cooked when eating out

What do I do after treatment?

  • Continue to follow these guidelines until your health team advises you otherwise
  • If you develop a fever, severe muscle aches, confusion or vomiting contact your hospital. They may want to examine you and do a blood test.
  • If you develop listeriosis you will be treated with antibiotics and you can continue alemtuzumab treatment once the infection has cleared.

What do I need to do now?

  • Check the temperature of your fridge
  • Dispose of all foods past their ‘use-by’ date
  • Place food stickers on each refrigerated item
  • Read our guidelines on food storage
  • Clean you fridge thoroughly with soap and water
  • If you would find it useful, use the food storage log

Further information

  • Visit
  • If you have any outstanding questions please ask your MS team or consult your listeriosis prevention pack