Nutrition and daily life

Food hygiene: everyday kitchen habits

Knowing which foods are risky is half the job; the other half is the simple habits repeated in the kitchen every day. This topic gathers practical tips on keeping food safe from shop to plate, handling leftovers, bringing food to hospital and eating away from home.

Last updated: 3 October 2026~6 min read

A clean, translucent kitchen surface glowing with soft teal light on a dark navy background, with a few luminous containers on it. — **Figure 1.**Concept: a clean kitchen is where safe food begins.

01Short answer

Food hygiene rests on five keys: keep clean, separate raw and cooked food, cook thoroughly, keep food at safe temperatures, and use safe water and raw materials. The fridge should be 4–5 °C or colder and the freezer −18 °C. Put cooked food in the fridge within two hours, eat it within a day or two and reheat it only once, until steaming. Throw away soft foods, bread and jam with visible mould. Change kitchen sponges and cloths often. A family member with diarrhea or vomiting should not cook. Away from home, choose freshly cooked hot food. Your hematology team will tell you whether you need stricter rules.

02Simple explanation

Germs cannot be seen, but they multiply very quickly in food left in a warm room, in a damp sponge or on a chopping board. Daily habits reduce the chance of them getting into food.

WHO offers five keys: keep clean, separate raw and cooked, cook thoroughly, keep food at safe temperatures, and use safe water and raw materials. These rules help everyone.

Cold slows germs down but does not kill them. Heat destroys them. That is why food should be kept either cold or hot, not at room temperature for long.

Leftovers are handy, but they have a time limit. The best approach is to cook small portions or to freeze extra food straight away.

Food hygiene is a job for the whole family. Everyone who cooks should know the same rules; it is one of the greatest forms of care for the patient.

03Scientific explanation

The temperature danger zone: according to WHO, germs multiply quickly at about 5–60 °C. US agencies advise that perishable food should not stay at room temperature for more than two hours, or more than one hour when it is hotter than 32 °C. The UK Food Standards Agency advises keeping the fridge below 5 °C; US agencies give 4 °C or below.

Freezing and mould: according to the USDA, freezing at −18 °C stops germs from multiplying but does not kill them; thawing in the fridge is safest. In soft foods (bread, jam, soft cheese, cooked dishes), mould can spread deeper than the eye can see, so these foods should be thrown away. Listeria, meanwhile, can grow even in the fridge.

Evidence on the neutropenic diet: a 2008 randomised trial in patients receiving AML induction found no difference in infections between a cooked-only diet and a diet that allowed raw fruit and vegetables. A 2019 meta-analysis also showed that a strict diet did not reduce infections.

Newer data: a meta-analysis published in 2026 (15 studies, 4,320 patients) found no overall difference; however, in randomised trials in blood cancers and transplant, bloodstream infections were less frequent with the neutropenic diet. The authors note that in high-risk situations, such as prolonged neutropenia and transplant, cautious food rules may still be justified. Either way, safe food handling remains the foundation.

04What happens in the body?

Shopping

Check that packaging is intact and look at use-by dates. Pick up chilled and frozen items last and, if possible, take them home in a cool bag. Pre-cut fruit, ready-made salads, loose spices and unpasteurised dairy from the market are riskier when immunity is low. Do not buy bruised, rotten or mouldy produce.

The fridge and storage

Keep the fridge at 4–5 °C or colder; a fridge thermometer helps. Store raw meat, chicken and fish in closed containers on the bottom shelf, with ready-to-eat food above. Do not overfill the fridge, wipe up spills straight away and wash the shelves regularly. Writing the date on opened containers is a handy habit.

Translucent shelves in cold blue light on a dark navy background, with closed containers neatly arranged on them. — **Figure 2.**Cold slows germs down, and good shelf order prevents contamination.

Leftovers

Divide cooked food into small, shallow containers and put it in the fridge within two hours. Eat it within a day or two; if you need to keep it longer, freeze it straight away. Reheat only once and until it is steaming hot all the way through; stir the middle when using a microwave. When in doubt, throw it out.

Soft golden waves of steam rising from a translucent bowl on a dark navy background. — **Figure 3.**Leftovers are reheated once, until steaming hot all the way through.

Sponges, cloths and boards

Damp sponges and cloths are a friendly home for germs. Change them often, or wash them in hot water and let them dry. Use separate towels for hands and for dishes. Keep a separate chopping board for raw meat and wash it in hot soapy water after use. Keep pets off kitchen surfaces.

Who should cook?

Everyone should wash their hands before eating and after touching raw food. A family member with diarrhea, vomiting or a fever should not cook until at least two days after they feel better. Before bringing home-cooked food to hospital, ask about the ward’s rules; cook it fresh and deliver it quickly in a closed container and a cool bag.

Eating away from home

Choose food that is freshly cooked and served hot. Open buffets, salad bars, street food and food that has been left out for a long time are riskier. Discuss with your team when you can go back to restaurants; rules may be stricter, especially after a transplant.

05From shop to plate: the daily cycle

At each stage, one simple habit lowers the risk.

1ShoppingDates, packaging, chilled items last.

2StorageFridge at 4–5 °C, raw meat on the bottom shelf.

3PreparationClean hands, separate boards, a clean sponge.

4LeftoversInto the fridge within two hours; reheat once.

Less riskSimple habits reduce food-borne infections.

The whole familyEveryone who cooks knows the rules.

If signs appearCall straight away with a fever or severe diarrhea.

06Storing food at home: a simple guide

Food	How to store	General rule
Cooked leftovers	In the fridge within two hours, in shallow containers	A day or two; reheat once until steaming
Raw meat, mince, chicken	In a closed container on the bottom shelf	Cook mince and chicken within a day or two
Frozen food	−18 °C or colder	Thaw in the fridge; do not refreeze after thawing
Bread, jam, soft cheese	Dry, clean, in a closed container	If mould appears, throw the whole item away
Cut fruit and vegetables	In a closed container in the fridge	Eat the same day
Eggs	In the fridge, in their box	Do not use cracked eggs

* This table is general information. After a transplant or during prolonged neutropenia your centre may apply stricter rules; follow them.

07Key terms

Food hygiene: Habits that keep food safe from purchase to eating.
Danger zone: About 5–60 °C; germs multiply quickly in this range.
Cross-contamination: The transfer of germs from raw food to ready-to-eat food, hands or surfaces.
Mould: A fungus that grows on food; in soft foods it spreads deep inside.
Listeria: A bacterium that can grow in the fridge.
Norovirus: An easily spread virus that causes vomiting and diarrhea.
Cool bag: An insulated bag that keeps food cold on the way.
Neutropenic diet: A diet that strictly limits raw foods; its benefit is debated.

08Key points

Five keys: clean, separate, cook, temperature, safe water.
Fridge at 4–5 °C, freezer at −18 °C.
Put leftovers in the fridge within two hours.
Reheat food once, until steaming.
Throw away soft foods with mould.
Change sponges and cloths often.
A family member who is ill should not cook.
Your team will tell you if stricter rules apply.

09Frequently asked questions

Can I cut off the mouldy part and eat the rest?

In soft foods (bread, jam, soft cheese, cooked dishes) mould spreads deep inside without being seen, so throw them away whole. When immunity is low, it is better not to take chances with hard foods either.

Can I cook food for several days?

Yes, but freeze the extra portions straight after cooking; when needed, thaw one in the fridge and reheat it until steaming. This saves time and keeps food safe.

Can my family bring home-cooked food to hospital?

Many wards allow it, but rules differ. Ask in advance, cook the food fresh and deliver it quickly in a closed container and a cool bag.

Can my pet be in the kitchen?

Keep pets off the table and kitchen surfaces, and wash their bowls separately. Wash your hands after touching an animal.

Is restaurant food completely off limits?

Not always. Many centres allow freshly cooked hot food but advise avoiding buffets and salad bars. After a transplant or with very deep neutropenia, the rules may be stricter.

Which signs can point to a food-borne infection?

A fever, severe or frequent diarrhea, repeated vomiting, abdominal pain or blood in the stool. With any of these, call your hematology team straight away.

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.

Which kitchen hygiene rules matter most?
How long can leftovers be kept, and how should they be reheated?
What should family members watch when they cook for me?
Do these rules still apply once my neutrophils recover?

My questions

12Sources

World Health Organization (WHO). Five keys to safer food manual
World Health Organization (WHO). Food safety — fact sheet
Centers for Disease Control and Prevention (CDC). Safer Food Choices for People With Weakened Immune Systems
FoodSafety.gov (U.S. HHS). 4 Steps to Food Safety
FoodSafety.gov (U.S. HHS). Cold Food Storage Chart
USDA Food Safety and Inspection Service. Leftovers and Food Safety
USDA Food Safety and Inspection Service. Molds on Food: Are They Dangerous?
USDA Food Safety and Inspection Service. Freezing and Food Safety
U.S. Food and Drug Administration (FDA). Selecting and Serving Produce Safely
Food Standards Agency (UK). Chilling
Memorial Sloan Kettering Cancer Center. Food Safety During Cancer Treatment
Journal of Clinical Oncology, 2008. Randomized comparison of cooked and noncooked diets in patients undergoing remission induction therapy for acute myeloid leukemia
BMJ Supportive & Palliative Care, 2019. Neutropenic diets to prevent cancer infections: updated systematic review and meta-analysis
JCO Oncology Practice, 2026. Neutropenic Diet Versus Liberalized Diet in Patients With Cancer: A Systematic Review and Meta-Analysis

Medical disclaimerThis information is for educational purposes only and does not replace medical advice.

Last updated: 3 October 2026← Back to the list

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