Was reading a forum on different types of kitchen counter tops here and someone wrote this
So, is it hooey? Would granite or similar still be preferable (to both wood and acrylic)?
Conventional wisdom suggests that bacteria would multiply on a wooden cutting board, what with all the grooves and niches for the bacteria to crawl into…
I’d assume a smooth granite countertop would just be too harsh (or sparse) of an environment for bacteria to live on.
It’ll be interesting to see an expert’s take on the matter.
Are we talking about counter tops, or cutting boards here? Cutting boards will be constantly damaged by knives, forming tiny cracks for bacteria to survive in. Counter tops won’t take that kind of abuse.
Some woods apparently contain chemicals with anti-bacterial properties. But the idea of bacteria multiplying and growing on them is a little odd. Bacteria have to have food to grow. While there might be food particles in the surface of the cutting board, basic sanitary precautions are more than enough to prevent problems. A little sanitizer (bleach water) or air drying are good enough – most foodborne-illness-causing bad guys are going to die off rather quickly on dry wood, stone, metal, or any other surface that doesn’t provide them food.
Food Detectives proved that bit of conventional wisdom as wrong since the concluded the wooden cutting board smeared with raw chicken had no more bacteria than a plastic one. Apparently the wood does have some kind of natural anti-bacterial nature.
I’m surprised by the inclusion of glass.
I would have guessed glass as a less hospitable environment than wood or plastic. Does anyone have a link to evidence of glass as a good breeding ground for bacteria?
If I may piggyback on this one. I once dropped the “wood is naturally anti-bacterial” factoid on someone and her response was that any surface that has dried thoroughly is free of bacteria. Is this true?
I have little doubt that glass is naturally more an inhospitable environment for bacteria than wood or plastic, but the fact that glass absolutely wrecks knives due to its hardness often precludes it from being considered a decent cutting-board material (and I can’t imagine it being a countertop material).
Isn’t the availability of food less to do with how much much you clean and more with how many microbe populations there are to eat it?
Drying is definitely going to help prevent the bacteria from multiplying, though I would not believe that all “dry” surfaces are inherently bacteria free.
Remember also, a potentially significant part of the “wood is better” argument is that plastic cutting boards will harbor water inside the surface scratches because plastic is not absorbent. Even if that plastic cutting board is wiped dry, and appears to be dry, it may not actually be dry.
I say hooey. There’s a reason restaurants are required to used stainless steel or some sort of Corian-type materials for their countertops.
Is that reason based on the latest research? Apparently not.
Yes, the reason is conventional wisdom, which has been demonstrated to be incorrect. I have read multiple independent studies, that replicated this result of wood either not harboring any more bacteria than plastic and in most of them, they found substantially less, sometimes no, bacteria on the wood. One study was conducted on well used plastic an wooden cutting boards, and in that one plastic fared much worse. The little scratches in the plastic held moisture and harbored bacteria while the older well used wooden one did not hold measurable bacteria. My own speculation is that the wood wicks away moisture even in the cuts and so is less hospitable. I would like to see the studies done with wooden end grain vs side grain. Butchers blocks are end grain and many home cutting boards are not.
Note: bamboo is not wood, and I have not seen it in any bacteria study, but cooks have noted that one must be more careful about drying bamboo because it has a higher tendency to mold or mildew. Bamboo is harder than most wood, but more porous on the end grain. It also may lack the antibacterial properties found in lignins.
On hand washing studies, the key to washing away bacteria is breaking up fat deposits on the surface of the hand. Now, I know that it is non trivial to remove the greasy film on some plastic dishes, so I wonder if that is a factor in the safety of cutting boards.
There seem to be a lot of misconceptions about how contamination works.
For a cutting board/countertop, food poisoning, which is what you get from ingesting toxins, is not much of an issue. (Staph is a semi-exception). It would be tough to ingest enough toxins transferred by your cutting board to get sick, even with a minimal wipedown. Botulism, for instance, doesn’t usually grow inside the body.
The primary problem with surface contamination is foodborne illness. These are bacteria or viruses or fungi or parasites that infect you. These microorganisms generally need a few things to live. Moisture and food are the big ones. Sugar and honey are pure food, but are so hygroscopic that there is no free water and microorganisms cannot survive. Pure water will also not harbor baddies, because they have nothing to eat (though other organisms like algae and stuff will happily set up shop and this will provide food later on). The danger zone is a moistish surface with available food – like raw meat left sitting out.
A clean dry surface is pretty deadly to most critters that will make you sick. So, if you cut up some chicken, rinse the board off but miss a colony, and let it dry out, you’re not likely to get sick from contaminating your next meal – the colony will die. On the other hand, if you cut up chicken and wash the board with soap and water, but miss a small colony of bacteria, and then cut up some veggies which pick up that colony, you might get sick.
So you have four options to avoid getting sick: You can clean the surface so well that all the pathogens are mechanically removed (good luck). You can treat the surface with a poison, like Lysol or bleach water. You can heat the surface, by boiling or autoclaving, etc. Finally, you can just let nature take its course – the bacteria will eat until the food is all gone and die, or they will dry out and die as all the water goes away.
So, in the home context, you rely on a combination of these – washing the board with soap and water to mechanically remove most of the food and bacteria, then letting the surface dry to kill the rest. Wood has chemicals that the pathogens don’t like; glass dries fast and is non-porous so mechanical methods work better, etc.
The difference between the materials is not one of letting bacteria grow; it’s better to think about them as which one is most easily made inhospitable by one of the above methods. Stainless countertops are used because in a restaurant, because there isn’t as much downtime between meals. It’s much easier to sterilize a stainless steel countertop by using a sanitzer chemical and a wipedown. Of course, using a steel cutting board would be murder on knives. For cutting boards, you cut in order of danger – raw things like lettuce get cut up first, and raw meats like chicken get cut last (cooking obviously kills the pathogens, so cooked chicken would be safe to cut earlier). Or, you can use multiple boards. But the takeaway for home cooks is that any normal material is going to be fine as long as you clean the board well and let it dry out. It won’t be sterile, but the organisms that like to live in you aren’t usually ones that like to live on dry, clean surfaces.