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Immunity and infection prevention

Food, water and infection

The main article (“Food safety”) explains nutrition. This topic is only about food safety: preventing infections spread through food and water.

Last updated: ~1 min read
Two boards in a kitchen.
Figure 1.Separate boards for raw and ready food.

01Short answer

Bacteria (Salmonella, Listeria, E. coli), parasites and sometimes fungi can be passed on through food and water. When immunity is weak, these infections are more severe. The core principles are the same for everyone: keep clean (hands, surfaces), separate raw and ready food, cook thoroughly, store at the right temperature, and use safe water and ingredients. The riskiest foods are raw or undercooked meat, eggs, fish and seafood; unpasteurised milk and cheese; raw sprouts; and ready meals kept for a long time. If you are unsure about tap water quality, drink boiled or bottled water. A very strict “neutropenic diet” is no longer advised for everyone; your team tailors the rules.

02Simple explanation

Clean, separate, cook, chill.

Raw meat, eggs, unpasteurised milk: risky.

Safe water.

03Scientific explanation

Listeria: can grow even in the fridge; unpasteurised cheese and ready-to-eat chilled foods are a risk.

Evidence: studies have not shown a strict neutropenic diet to be better than ordinary food-safety rules.

04What happens in the body?

Separate boards

Separate boards for raw and ready food prevent cross-contamination.

Cooked through

Cooking food thoroughly kills bacteria.

A steaming plate — Food, water and infection
Figure 2.Fully cooked food — Food, water and infection

Safe water

If unsure, use boiled or bottled water.

A glass and a sealed bottle.
Figure 3.Safe water — Food, water and infection

05Safe food

Four steps.

Clean — Hands and surfaces.1CleanHands and surfaces.
Separate — Raw and ready.2SeparateRaw and ready.
Cook — Thoroughly.3CookThoroughly.
Chill — Store properly.4ChillStore properly.

06Riskier and safer choices

RiskierSafer
Raw or undercooked meat, fishFully cooked meat and fish
Raw eggsWell-cooked eggs
Unpasteurised milk, cheesePasteurised products
Raw sproutsCooked vegetables or well-washed fruit
Leftovers kept a long timeFreshly prepared food

07Key terms

Pasteurisation
Heating to kill germs.
Cross-contamination
Germs passing from one food to another.
Listeria
A bacterium that grows even in the cold.
Salmonella
A bacterium found in eggs and poultry.
Neutropenic diet
A restricted diet during neutropenia.

08Key points

  • Food and water can carry infection.
  • Clean, separate, cook, chill.
  • Raw and unpasteurised foods are risky.
  • Boil water you are unsure about.
  • A strict diet is not needed by everyone.
  • Your team tailors the rules.

09Frequently asked questions

Can I eat fruit?

Usually yes, well washed; peeling is an extra precaution; ask your team.

Can I eat out?

Yes, avoiding risky dishes; during severe neutropenia, ask your team.

When will the rules relax?

As your immunity recovers (“Recovery of immunity”).

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Can I eat fruit?

  2. Can I eat out?

  3. When will the rules relax?

My questions

12Sources

  1. World Health Organization (WHO). Hand hygiene
  2. American Cancer Society. Infections in People with Cancer
  3. National Cancer Institute (NCI). Infection and Neutropenia during Cancer Treatment
  4. MedlinePlus (U.S. National Library of Medicine). Antigen
  5. MedlinePlus (U.S. National Library of Medicine). Antibody
  6. MedlinePlus (U.S. National Library of Medicine). Quantitative nephelometry test
  7. Journal of Clinical Oncology (ASCO), 2020. Hepatitis B Virus Screening and Management for Patients With Cancer Prior to Therapy: ASCO Provisional Clinical Opinion Update
  8. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: immunity
  9. Nature Reviews Immunology, 2016. Farber DL et al. Immunological memory: lessons from the past and a look to the future
  10. New England Journal of Medicine, 2007. Amanna IJ, Carlson NE, Slifka MK. Duration of humoral immunity to common viral and vaccine antigens
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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