Plastic

I have nothing against a plastic chopping board, and I understand perfectly well why there is one in almost every kitchen. It costs a few euros, it weighs nothing, it goes into the dishwasher and comes out white, and when raw chicken has been on it you can bleach the thing without a second thought. In a professional kitchen it is close to compulsory: the boards come colour-coded, one for meat, one for vegetables, one for fish, so that an inspector can see at a glance that the system is being kept. Whoever bought it was answering a real question, and it answers that question well.

The kettle got into the house the same way. It is light, it is cheap, it boils in two minutes, and it is what every shop sells.

What neither of them is ever judged on is how much of itself it leaves behind, which is an odd thing to leave out, given that one spends its life under a knife and the other spends its life full of boiling water.

What came off the board

In 2023 a group of American researchers did the obvious experiment, which somehow nobody had got round to before. They chopped. Ordinary boards, ordinary chopping, and then they went looking for what had come off into the food. Polyethylene, the soft white plastic most boards are made of, gave up the most, and scaled to the amount a household really cuts they put it at somewhere between 7 and 51 grams of board per person per year. Where you land in that range depends on how hard you cut, how often, and what your particular board is made of.

Fifty grams is a bar of hotel soap. It leaves in pieces far too small to see, and it leaves at the one moment when there is food under the knife. Nobody is being careless. This is what plastic does when a blade goes through it.

The kettle turns out to be front-loaded instead. When someone measured what a new polypropylene kettle puts into its first boil, the count ran into millions of particles per millilitre, and then fell away steeply as the kettle was used. Most of what a plastic kettle sheds it sheds in the first weeks of its life, into the water you make the morning's tea with.

Let me be careful here. Nobody has shown that a chopping board has ever made anyone ill. The research on what microplastics do inside people is young, and I am not going to pretend otherwise. What we do know is simpler. The material comes off, it comes off into food, and two separate teams have now measured how much. That is enough to change a habit, and no reason to worry.

Why the obvious fix makes it worse

The instinct with a scratched board is to clean it harder. Hotter water, more bleach, the rough side of the sponge, a longer cycle in the machine. That is what hygiene training teaches, and on plastic it works against you, because the scratches are the part that sheds. Anything that roughens the surface further, heat and strong detergent and scouring included, means the next chop takes a little more of the board with it. The board someone has kept spotless for six years is often the worst one in the drawer.

The other thing worth turning over is the belief that wood is the dirty option, since that belief is the reason most of us switched in the first place. When Dean Cliver's group at the University of California, Davis contaminated boards of both kinds on purpose and then went looking for the bacteria again, the wooden boards were the awkward ones: nothing multiplied on the surface and very little could be recovered from it, while the used plastic boards were holding their bacteria down in the knife scars. Wood is not sterile and it is not magic. It simply does not reward a knife the way plastic does.

So why is every restaurant still using plastic?

Because a professional kitchen is not run on what is ideal, it is run on what can be demonstrated to an inspector at nine in the morning. Colour-coded, bleachable, replaceable boards are what the hygiene systems were built around, so a chef reaching for one is doing the job exactly right. None of this is the restaurant's fault. At home the inspection is your own, and you are the only person in the chain who is free to choose differently.

What the old kitchens already knew

Walk into a kitchen that has been cooking for a century and the materials come down to a short list: wood, copper, cast iron, steel, glass, enamel. Nobody chose any of it out of concern about microplastics. They were chosen because they survive being used, and because they stay pleasant to use while they survive. A wooden board improves with a little oil, a steel pot is still a steel pot forty years later, and glass tells you what is inside it while adding nothing of its own.

They were chosen for how they look and how they last. They answer this question too.

How to change it, in order

Nothing here needs buying until the last two lines.

• Retire the worst board you own. Not all of them, just the one that has gone grey and furred and criss-crossed with cut marks. That is the board doing most of the shedding, and taking it out of the food rotation costs nothing.
• Keep hot and oily things off plastic. Heat softens the surface and fat carries away whatever comes loose, so the roast chicken and the hot loaf and anything straight out of a pan want a plate, a wooden board or an upturned enamel dish instead.
• Take the boards out of the dishwasher. A long hot cycle with strong detergent ages a plastic board quickly and warps a wooden one. Hot soapy water, a quick scrub and drying it standing on its edge is less work anyway.
• Let food cool before it goes into plastic, and never heat it there. That one habit covers the containers, the tubs and the lids in a single move.
• With a new kettle, boil it three or four times and pour it away. The shedding is heaviest at the start and falls off with use, so the first few boils down the sink take most of it with them. After that, descale with vinegar when it needs it rather than letting it scale and pit.
• Keep one plastic board for raw meat if that is how your kitchen runs. This is not a rule about purity. Raw chicken has risks of its own, and a board you can bleach is a sensible answer to them. Replace it once it scars.
• Then, and only then, buy a board. Solid wood, hard and close-grained, end grain if you can find it, and without much glue in it. One good one lasts decades and only gets better looking. The boards and the glass I keep food in are in the food storage and boards group of the Hearth directory.
• And when the kettle finally dies, replace it with glass or steel. Not before. A working kettle is not waste worth creating, so the swap belongs at the end of its life, and the same goes for the pans in the cookware group.

The order matters more than the list does. Everything free comes first, and what gets bought at the end of it is not a gadget, it is material: wood, glass, steel.

After the swap

Very little, on the day. Nobody has ever felt different for cutting an onion on oak. What changes is a count: one surface that used to end up in the food, quietly, at every meal, and now does not.

This is the fourth principle of the Hearth, that the only thing I really buy in a kitchen is the surface that touches the food, and the fifth, that glass, wood and enamel age better than plastic. Neither is a rule about being good. They are about which materials stay out of the conversation.

The body never trusted plastic against hot, oily food. For once the old instinct has the data behind it.