Fish safety: good for you, but only cooked
Fish provides protein and omega-3 fatty acids. But raw and undercooked fish, shellfish and cold-smoked fish can carry bacteria and parasites. This section explains how to eat fish safely during treatment.
01Short answer
02Simple explanation
63 °C, opaque.
No sushi or raw fish.
No cold-smoked fish.
Canned is usually fine.
03Scientific explanation
FDA: fish should be cooked to an internal 63 °C (145 °F); cold-smoked fish carries a Listeria risk.
WHO: foodborne illness is more severe in people with weakened immunity; the five keys are keep clean, separate, cook thoroughly, keep food at safe temperatures, and use safe water and raw materials.
04What happens in the body?
Choosing
Fresh fish has bright eyes, firm flesh and a fresh smell.
Shellfish
Cook prawns, mussels and squid fully; throw away mussels that do not open.
Neutropenia
When neutrophils are low, even ordinary germs can cause serious infection, which is why the rules are stricter.
General rules
This section is part of the general food-safety rules in “Handwashing: the simplest protection” and “Eggs and dairy: safe choices” and “Food safety: four simple rules”.
05Safety: four steps
Check, swap the risky, prepare properly, use in time.
06Key points at a glance
| Topic | In brief |
|---|---|
 Choosing | Fresh fish has bright eyes, firm flesh and a fresh smell. |
| Shellfish | Cook prawns, mussels and squid fully; throw away mussels that do not open. |
 Neutropenia | When neutrophils are low, even ordinary germs can cause serious infection, which is why the rules are stricter. |
 General rules | This section is part of the general food-safety rules in “Handwashing: the simplest protection” and “Eggs and dairy: safe choices” and “Food safety: four simple rules”. |
07Key terms
- Cold smoking
- Smoking without high heat, so germs are not killed.
- Omega-3
- Beneficial fatty acids in fish.
- Foodborne infection
- An infection spread through food or water.
- Neutropenia
- Low neutrophils.
08Key points
- Cook it fully.
- Avoid raw and cold-smoked.
- Cook fresh fish soon.
- When in doubt, throw it out.
- Call if you have a fever.
09Frequently asked questions
Is hot-smoked fish OK?
Usually, if reheated until steaming; ask your team.
Should I take fish-oil capsules?
Not on your own; with low platelets they may affect bleeding.
Are these rules for ever?
No. They are usually relaxed as blood counts recover; your team will say.
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.
Is hot-smoked fish OK?
Should I take fish-oil capsules?
Are these rules for ever?
12Sources
- World Health Organization. Five Keys to Safer Food manual
- World Health Organization. Food safety fact sheet
- U.S. Food and Drug Administration. Safe Food Handling
- National Cancer Institute. Eating Hints: Before, During, and After Cancer Treatment
- Centers for Disease Control and Prevention (CDC). About C. diff
- National Cancer Institute (NCI). Nausea and Vomiting and Cancer Treatment
- National Cancer Institute (NCI). Appetite Loss and Cancer Treatment
- American Cancer Society. Nutrition for People with Cancer
- World Health Organization (WHO). Healthy diet — fact sheet
- Clinical Nutrition, 2021. ESPEN practical guideline: Clinical Nutrition in cancer