Cutting both ways

When it comes to food safety, plastic cutting boards may have a slight
advantage over wooden, but not for the reasons you might expect.

When it comes to food safety, plastic cutting boards may have a slight advantage over wooden, but not for the reasons you might expect.

Wooden cutting boards have got a bit of a bad rap since the 1980s, when they were banned from use in foodservice outlets because they were believed to harbour bacteria and be difficult to clean. This ban had a snowball effect in North America as well. Many perceived wooden boards as less safe than plastic boards – a misperception, says one food safety expert.

“A lot of that theory came from Europe,” says Prof. Keith Warriner, professor and Food Safety and Quality Assurance program director, at the University of Guelph. “The evidence for that was really shaky; it’s basically anecdotal. We can see a lot of regulations that have come through that are based on this anecdotal evidence rather than scientific research.”

Since then, Warriner says, many researchers have put pathogens onto cutting boards and studied how long bacteria such as E. coli and salmonella attach to the boards, how they cross-contaminate products and how easy they are to clean. The results? Far from being a greater safety risk, wood may offer advantages over plastic. An oft-cited study from the Food Research Institute at the University of Wisconsin in 1994 says: “Cutting boards of plastic and wood contaminated experimentally with bacteria,” came to the surprising result that wood possesses substantially better hygienic characteristics than plastic. “Wooden boards that had been used and had many knife cuts acted almost the same as new wood, whereas plastic surfaces that were knife-scarred were impossible to clean and disinfect manually . . . More bacteria are recovered from a used plastic surface than from a used wood surface.”

MERITS AND DRAWBACKS
Warriner says hundreds of similar studies refute the notion that wood is unsafe in cutting boards. Thus he has concluded that “both wooden and plastic cutting boards have got advantages and disadvantages, so overall there’s no real issue about using either of them.”

“There is not one paper out there that says wood is bad and plastic is good,” he notes, but he cautions foodservice operators to should replace boards often.

Wood has the advantage of drying quickly, and although it absorbs bacteria and may release them later, these bacteria tend to die off so that they are much less of a concern than first thought.

However, wooden boards require greater care when washing and sanitizing, and require mineral oil to preserve them and inhibit penetration of water. Wood also is more expensive, especially hard woods such as maple and birch, which are generally thought to resist absorption.

Plastic boards can be washed in a dishwasher, whereas wooden boards may dry out and crack in high temperatures. Plastic is a harder surface, and so absorbs fewer pathogens.

Generally, you will spend less on a plastic board, but you will need to replace it more frequently due to deep knife cuts. In fact, many, including the Canadian Food Inspection Agency, recommend you use separate boards to prepare different foods: “Cut and prepare raw meat, fish and poultry on a separate cutting board from that used to cut ready to eat vegetables, fruit or other foods.”

“Wood is the traditional material,” Warriner notes, “. . . and it is a very natural absorbent. It absorbs moisture obviously, but bacteria as well.

“So one would have thought, surely then the wood is worse because it absorbs it rather than just prevents it from being removed from the surface, and there is a cause for that. Yes, it does absorb, but the bacteria do die off because the board dries out fairly quickly, being wood, whereas with plastic, which is impermeable, it doesn’t.”

Plastic cutting boards, which have an impermeable layer that prevents bacteria from absorbing into the material, should be relatively easy to clean, but that’s not the case, he says. “With plastic, because of the rigidity, when we cut into it with a knife, we cut grooves into it, a bit like a old record player, so what you get is bacteria going into those grooves and they are not easily removed once they get into those grooves.”

Wooden boards are subject to the same grooves, but because water sits on top of a plastic board, bacteria have the moisture to grow. Bacteria need food (food debris), warmth (room temperature) and moisture to grow: with plastic, you have all three of these elements, and because you can’t clean a very scratched cutting board very well, bacteria grow more and survive longer. So, if you were to put raw chicken on plastic, for example, give it a rinse, let it air dry, then put ready-to-eat lettuce on top, says Warriner, it’s a recipe for disaster.

PLASTIC and allergens
When it comes to harbouring allergens, plastic may have a slight advantage. “Very few people talk about allergens when they’re talking about cutting boards. Allergens like peanuts, egg, milk, even some meat proteins, would be a higher risk in wooden cutting boards because they absorb what they last had on them.”

Plastic “can be a bit safer” in that allergens can be relatively more easily removed from plastic than they can be from wood, a factor those who offer, or are thinking of offering, gluten-free pizza may want to consider. This is another reason colour-coded boards are a good idea.

CLEANING AND SANITIZING
Although there are proponents of each camp, everyone agrees, keeping your boards safe comes down to proper cleaning and sanitizing. One error people make, says Warriner, is that they keep the boards too long and don’t sanitize them. There are many methods for cleaning and sanitizing, the most common of which is washing with hot, soapy water, and sanitizing with chloride. The best method he has discovered is to use alcohol wipes or alcohol-based sanitizers or gels, which in his view are better than chlorine.

His own studies on cleanliness in hotel rooms and hundreds of similar papers, support the method. One 2011 study, “Comparison of Sanitizing Methods for Reduction of Attached Microorganisms on Various Kitchen Cutting Boards,” concluded the following: “Order of efficacy in removing E. coli O157: H7 was as follows: alcohol > chlorine > wet > dry paper towel.”

 Because food inspections are done at the municipal and sometimes provincial level, it is wise to consult your own food safety authority if you have questions or concerns. Maxine Marchenski, of the Vancouver Island Health Authority, says boards, blocks and surfaces should be easy to clean and sanitize. The Authority follows the Food Premises Regulations of the B.C. Public Health Act, Reg. 210/99, but the legislation differs from province to province.

The B.C. regulations do not stipulate materials to be used but foodservice outlets are required to have a written food safety plan and a food sanitizing plan. Inspectors review that strategy, checking the strength of the cleaning solutions used. As long as a solution meets the standards, it is acceptable.

She says wood in the past tended to split, creating deep grooves, but with teflon coatings, that is not a problem anymore.

Scott MacLean, executive director of the Health Protection Branch for the New Brunswick Department of Health, says his province require boards to be “smooth and cleanable.” Materials aren’t stipulated, but boards are required to be of “food-grade material (certified by a third-party certification body such as the National Sanitation Foundation or the Standards Council of Canada). If using a wooden board, he recommends it be “seamless, and of a hard wood such as maple or birch, and non-toxic.”

The pre-2009 regulations in his province used to be specific, stipulating materials such as stainless steel. “Now they are more concerned with outcomes,” says MacLean. In other words, it’s important they meet the standards, and less important how they do it.

“As long as you wash, rinse and sanitize, you should be fine,” says MacLean.