by D-Machine | 2025-12-15 07:38:06+00:00
Okay, probably no one cares, but I wanted to look into this "biofilm" claim, because it is quite incredible but makes no real sense, but on the surface, seems to be from a legitimate paper that is reasonably well-cited. Looking into it, I would say it is clear the stackexchange poster definitely doesn't know what they are talking about, and seriously misrepresents the study [1], which is quite terrible.

As a first bad sign, though this paper is published in 2018, the authors fail to cite any of the numerous prior studies showing no differences or superior behavior of wood relative to plastic, indicating some pretty glaring biases right at the outset. Moving on:

> "Formation and quantification of biofilm. To verify if all 10 strains were biofilm producers, we used plastic, wood, and glass circles with a diameter of 1 cm. These materials were washed, dried, and autoclaved in a Petri dish. Next, with sterilized tweezers, each circle was placed on the bottom of a well in a 24-well plate. Plastic and wood circles were obtained by cutting samples from commercially sold boards. [...] The Salmonella strains were incubated in Luria-Bertani (LB) broth at 35°C/24 h. Next, the culture was diluted [...]. Aliquots of 300 lL were distributed in triplicate into the wells, and the plates were incubated at 35°C/96h."

Obviously no cutting board is ever in such conditions, and even still, their Table 1 shows in fact that there is NO significant difference (4 plastic vs 6 wood) in samples in biofilm growth. At no point do they ever show meaningful growth of biofilm on a washed cutting board allowed to dry.

They also don't mention if these are new cutting boards, which invalidates the whole thing, since the problem is that plastic cutting boards gouge and then don't wash properly. Every decent study looks at used or gouged boards as well, otherwise they don't reflect real-world usage.

> "Each Salmonella strain was incubated in BHI broth at 35°C/24 h and diluted [...], and 1 mL was uniformly spread on a chicken breast surface, previously thawed, and Salmonella-free. Next, each [cutting board] surface was contaminated by rubbing with the contaminated chicken for 30s. This step was performed in duplicate to assure the transfer of Salmonella from the cutting surface to the cucumber because a cotton swab would capture most cells on the first rub (item a, below mentioned), leading to an undetectable count in the vegetable due to the low number of residual cells (item b, below mentioned)"

You can judge if this is realistic or not. Also, if a simple swab is removing so much cells that they couldn't detect anything in the vegetables later, how could washing not possibly be removing the same? This is an extremely suspicious comment in general. Let's see:

> "the contaminated boards were washed before they were exposed to the cucumber. The washing was performed with hot running water for 10s, vigorously scrubbed with a new sponge moistened with neutral liquid detergent, rinsed in hot running water, and dried"

Surely not, but it sounds like they are washing with a dry sponge moistened only with detergent? Dried for how long? Because we already know it needs to be hours in all cases, this is nothing new. Was the sponge abrasive or a soft one? You need an abrasive and lots of hot water, not a dry, soft sponge "moistened" only with pure detergent, and ten seconds of scrubbing if you want washing to do anything at all, especially smeared chicken breast. Smeared chicken always needs a two-phase wash, once with a harsh abrasive tool (scouring pad or brush) with soap, then a rinse, and then again with a normal sponge, or you obviously have chicken bits left behind. Nothing about the procedure sounds adequate.

> "As expected, when the surfaces were unwashed after contact with the contaminated poultry, all strains were recovered. Regarding the washed surfaces, the wooden one showed the highest positivity in recovery of pathogens, occurring in 9 out of 10 tested strains. Fewer positive samples were observed on plastic and glass surfaces, 3 of 10 and 1 of 10, respectively. According to the Cochran test, both surfaces differed significantly from wood, showing them to be the easier materials to be sanitized, in the absence of biofilm ( p < 0.05)."

The inexact and high p-value means this is exceedingly weak evidence (actually not significant if you account for multiple comparisons), and what is a "positive sample" in terms of actual counts is not defined, which is also highly suspect. Also why are we using such a weird statistical test? Real studies will have log reductions or actual counts (e.g. [3] - which also looks to find plastic to be worse, from what I can read). Very p-hacky.

"All samples of cucumbers displayed the presence of Salmonella Enteritidis, regardless of the cutting surface material unwashed [sic]. After washing, the wooden cutting surface showed the highest transfer of bacterial cells to cucumber, followed by plastic and glass surfaces, which again were shown to be the more hygienic materials, differing statistically from wood. On the contrary, all cucumber samples were contaminated with Salmonella Enteritidis, even after washing the cutting surface in the presence of biofilm [emphasis mine]"

So in one case (salmonella without biofilm) wood looks worse with marginal significance, but in all cases where the salmonella is biofilm-producing, it doesn't matter what the board is made of. Pretty unconvincing.

So, yeah, nope. Use plastic or wood, just clean properly.

[1] Dantas, S. T., Rossi, B. F., Bonsaglia, E. C., Castilho, I. G., Hernandes, R. T., Fernandes, A., & Rall, V. L. (2018). Cross-contamination and biofilm formation by Salmonella enterica serovar Enteritidis on various cutting boards. Foodborne Pathogens and Disease, 15(2), 81-85. https://scholar.google.ca/scholar?output=instlink&q=info:H9T...

[2] Bischoff, A., Alter, T., & Schoenknecht, A. (2025). Hygienic Evaluation of Wooden Cutting Boards: Microbiological Parameters. Journal of food protection, 88(9), 100576. https://doi.org/10.1016/j.jfp.2025.100576

[3] Pegueros-Valencia, C. A., Lucero-Mejía, J. E., Hernández-Iturriaga, M., & Godínez-Oviedo, A. (2025). Assessing Salmonella enterica biofilm formation in frequent scenarios of chicken handling in domestic kitchen environments. Food microbiology, 132, 104849. https://doi.org/10.1016/j.fm.2025.104849