Wooden or plastic chopping board? What the science says

«Wood is unhygienic, it fills up with bacteria.» That is the objection we hear most. And it comes from an official recommendation that never had a study behind it.

What is interesting is what happened when someone set out to measure it in a laboratory.

Where the belief comes from

In the eighties and early nineties, the United States department of agriculture recommended using plastic boards instead of wood in home kitchens. The reasoning seemed like common sense: wood is porous, plastic is not, so plastic cleans up better.

The problem is that it was just that, common sense. There was no research to back it up.

What the UC Davis laboratory found

In 1994, a team from the food safety laboratory at the University of California, Davis, made up of Ak, Cliver and Kaspar, decided to check it. They applied pathogenic bacteria, salmonella among them, to wooden boards and to plastic boards, and measured what happened to them.

The result was the opposite of what was expected.

On the wooden boards, the bacteria could no longer be recovered a few minutes after being applied. They disappeared from the surface and could not be cultured back.

On new plastic boards, the bacteria survived. And if they were left overnight at room temperature, they multiplied.

The detail that changes everything: knife cuts

Here comes the part that really matters, because nobody uses a brand new board for ten years.

The researchers repeated the experiment with used boards, covered in knife marks.

Used wood behaved almost the same as new wood. The cuts did not change the result.

Scratched plastic, on the other hand, was impossible to clean and disinfect by hand. The bacteria took shelter inside the knife grooves, and neither the scourer nor the washing-up liquid reached them. And it got worse when there was grease left behind, from chicken for example.

That is the real difference. It is not so much which material holds up better on day one, but which one is still safe after two years of use.

Why wood behaves this way

The most widely accepted explanation has to do with the structure of the wood itself. The bacteria that land on the surface are drawn into the fibres along with the moisture, and in there, with no free water available and with the natural compounds of the wood all around, they neither survive nor manage to come back up to the surface.

Put another way: the wood swallows them and does not give them back.

One necessary note. This is a laboratory finding about how the material behaves, not a promise that a wooden board is sterile. A wooden board has to be washed just like any other.

What this means in your kitchen

Always wash and dry it after use. Wood works in your favour, but it does not do your job for you.

Keep a dedicated board for raw meat and fish. This holds for any material. Cross-contamination is avoided by separating, not by picking the right board.

Never leave the board wet. Permanent moisture is the one thing that really can become a problem with wood.

Replace your plastic boards when they get badly scratched. A plastic board with a surface full of deep grooves is exactly the scenario that came out worst in the study.

Keep the wooden board oiled. A well nourished surface absorbs less liquid and cleans up with less effort.

When plastic does make sense

We sell wooden boards and even so there are cases where plastic makes sense, and saying otherwise would be selling smoke.

If you need to put the board in the dishwasher because of your job or out of habit, plastic is the option. In professional kitchens, where the protocol demands high temperature disinfection and colour coding by type of food, plastic is there for a reason.

For a home kitchen, where the board is washed by hand and dried, wood stands up to the comparison very well. If you are thinking of switching to wood, here are our kitchen boards.

Frequently asked questions

Is a wooden board more hygienic than a plastic one? According to the 1994 UC Davis study, bacteria stop being recoverable from wood within a few minutes, while on plastic they survive and multiply. The difference widens with use: scratched wood behaves like new wood, and scratched plastic is impossible to disinfect by hand.

Does wood absorb bacteria? It absorbs moisture and the bacteria with it, but inside the fibre they neither survive nor come back to the surface. That is precisely the mechanism that makes it safe.

Can I cut raw chicken on a wooden board? Yes, washing it afterwards with hot water and soap and drying it well. What we recommend, with any material, is to keep a board dedicated to raw meat and fish.

When should I throw out a plastic board? When it has deep, visible knife grooves. In that state it cannot be properly disinfected by washing it by hand.

Is a wooden board antibacterial? We do not use that term, because it describes a regulated property that does not apply to a kitchen board. What does exist is research documenting that bacteria do not survive well on wood. It is a finding about the material, not a function of the product.