Kitchen hygiene without running water

Pathogens get into food in three ways: via hands, surfaces and dishes. Running water normally helps twice over – it rinses dirt away and dilutes whatever remains. Without tap water both effects are lost. So soap, mechanical rubbing, separating dirty from clean and safe rinse water must take over this job.

Soap works because its molecules bind to fat on one side and to water on the other. This lets it loosen the greasy film in which germs cling, and the rinse water can carry it away. Time is what matters: rub hands thoroughly, including thumbs, between the fingers and the nails, then rinse with clean water.

Hand sanitisers are handy when water is short, but do not replace washing when hands are visibly dirty or greasy. They also do not work equally well against all pathogens. So before cooking and after using the toilet, always wash with soap.

For a washing station you need a container with a tap or a jug, soap, a catch bowl and paper towels or clean cloths, all in a fixed place. Waste water is disposed of, not reused. This way nobody dips their hands into a shared bowl where everyone's germs collect.

A particularly economical variant is the so-called tippy tap: a hanging container is tipped with a foot loop and releases a thin stream of water. Hands do not touch the container.

For washing up you need two or three bowls, detergent and clean cloths. A dishcloth used for days spreads germs rather than removing them – change it often and let it dry in between.

Washing up with bowls works like this: first scrape off or wipe leftovers thoroughly with paper. Bowl 1 holds warm water with detergent, bowl 2 clean rinse water. If you like, use a third bowl for disinfection according to the manufacturer's instructions. Then let the dishes air-dry rather than rubbing them with a possibly dirty cloth.

Clear the work surface and wipe it before and after cooking. Keep raw and ready-to-eat food apart and use separate boards, for example one for raw meat and one for bread and vegetables. Do not leave leftovers uncovered for hours.

Fewer dishes mean less washing-up: serve from the pot, and give each person a marked plate and mug that are reused. Disposable tableware only sparingly and as an exception – it quickly becomes a waste problem.

For hands, dishes and anything that touches food, use only safe, boiled or treated water. Utility water, for example collected rainwater, is not suitable for this unless it has been treated. Dispose of waste water away from water sources and food.

Disinfectants are only diluted according to the manufacturer's instructions and never mixed with each other. In particular, chlorine bleach must never come into contact with acids, such as vinegar cleaners, or with ammonia, because toxic gases are produced. This entry deliberately gives no concentrations.

Anyone with diarrhoea or vomiting should not cook for others. With severe or persistent symptoms, especially in children, older or weakened people, get medical help or call the local emergency number (112 in the EU).

The WHO's “Five Keys to Safer Food” begin with cleanliness: keep hands, surfaces and utensils clean, separate raw and cooked, and use safe water. Without running water these rules stay the same – only the means change.

A well-organised washing station takes about twenty minutes to set up but keeps the whole household healthier. It is best to set it up as soon as the water fails and make sure everyone knows where it is and how to use it – the children too.