I wanted to share the technical details I used to generate an article about cleaning methods for another site. The article summarizes the primary ways to address household cleaning for bacteria and viruses. The cleaning necessary is different, and spoiler alert, cleaning for viruses requires extra steps. This article will explore how I arrived at that conclusion by evaluating the content in each article reviewed. The content evaluation is mostly comprised of looking at graphs. To protect the copyrights of the original content creators, I have linked to the original articles rather than embedding the images within the article. After all, they did spend a lot of time and funding generating the data that we will be discussing today. It doesn’t hurt anyone to click on a link to see what’s being discussed.

Floor cleaning: effect on bacteria and organic materials in hospital rooms

This article can be viewed for free on the publisher’s site.

In the first article, various types of floor cleaning methods are evaluated. You’ll see in both Figure 1 and Figure 2, that two types of bacteria were tested. The graphs show the percentage of the bacteria left after mopping for each test performed. These graphs show a lot of variation. The numbers are generally less in the biotrace study, and it seems like all of the types of mopping are kind of equal at this point.

The differences start to appear much more in Figure 3. In this graph, you see the same information as in the previous two graphs. The primary difference is that Figure 3 shows the averages of all of the studies. The moist and we mopping look very different than the dry and spray mopping, especially in the case of the hygiena study.

Then we see in Table 1 a statistical test that actually communicates whether or not there were differences between the mopping techniques. We see that for the hygiena study the wet technique is better than the dry and spray techniques based on the p-value being less than 0.05. However for the biotrace study there is no difference between the wet technique and the other techniques. The discussion then talks about some of the limitations of the study. It appears that the hygiena and biotrace studies had different scales, and this, of course, will affect the results of the statistics ran. There is no mention of scaling the data to compare results between the two studies. This table is actually what gives the other figures meaning, and is where I drew my conclusions about what to recommend to the reader.

What this communicates is that for some bacteria, moist and wet mopping can reduce the amount of some bacteria present, but not necessarily all bacteria. The reason why I suggested wet mopping over moist mopping in my review comes down to prep time. The moist preparation of the mop includes soaking the mop head in nearly boiling soapy water, wrapping it in plastic, and leaving it alone overnight in an airtight space, like a household dryer. This is not easy to do. Whereas, with the wet method, you get a mop, get some warm water, pour some soap in, mix it up with the mop, and get to mopping, a much more friendly practice, easily adopted for a household.

Additionally, this source illustrates that having a surface wet, dripping wet, is important to reducing bacterial presence. I, personally, think that creating the expectation of a wet floor that has just been mopped, and transferring that expectation to something like a countertop will create a more solid visual for the reader.

Spread of bacteria on surfaces when cleaning with microfibre cloths

The primary researcher for this article has the full text available on her profile at ResearchGate.

The analysis in this article actually looked very different. The measurement metric for success and failure was different, coming from a source outside of the study. A predetermined standard for the acceptable number of bacterial colonies to be present was used to compare against the data collected. The trend of success or failure informed the conclusions generated by the study. Ultimately the author determined that cotton containing cloths transmitted less bacteria than microfiber cloths. A comparison proved to be statistically significant, though the structure of the statistical analysis isn’t clear.

Ability of cleaning-disinfecting wipes to remove bacteria from medical device surfaces

This article’s full text was made available by a Canadian website, Process Cleaning Solutions.

The statistics done in this paper are pretty straight forward. A series of un-paired t-tests were used to determine if a testing group was significantly different from other testing groups. The results are displayed visually in bar graph form with the % CFU remaining on the y-axis, and the treatment on the x-axis. CFU stands for colony forming unit, which is basically, the number of bacterial cells in the remaining in sample after the treatment. This means that, the higher the bar in the graph, the more ineffective the treatment was. The bars also include error bars, which are said to be standard error of the mean. Between three and five repetitions of testing were performed for each type of treatment.

This extent of analysis done in this study shows that bleach and treatment group three out-performed the other types of treatment groups on an unpredictable surface, and that a home bleach solution with a soaked gauze rag performs better than a store bought wipe.

I’m not sure that this is the most through analysis that could have been completed for this study. The sample size is small, and a non-parametric test, a Mann Whitney U specifically, would give more weight to the hypothesis that a store bought wipe will assist in controlling the spread of bacteria. To really hammer home this point, an ANOVA could have been completed. This would actually order the different treatment groups in terms of effectiveness instead of allowing the user to guess based on the visuals present, and this approach would account for the variation present in the mean standard error.

However, the background knowledge that bleach, which is the type of wipe used in treatment group three, is known to breakdown a lipid bilayer goes a long way in supporting the weaker statistics seen in this article. Bleach is basic, with a pH greater than seven, and causes the bonds the bind a lipid bilayer together to break apart. Lipid bilayers exist as the outside layer of all cells, including bacterial cells. So the findings that bleach and treatment group three are effective in lowering the percentage of CFUs is not surprising. What really elevates this study is that the authors evaluated smooth surfaces compared to rough or uneven surfaces. It is in this comparison that the home made bleach with a gauze rag has the most stark effect on remaining bacteria, taking the presence of Staph. aureus down to zero, with no error bar present. This is ultimately, why I am confident in relaying the information that creating your own bleach solution at home, and cleaning with a cotton cloth that can soak the area needing to be cleaned, will powerfully protect against bacteria.

Bacteria on smartphone touchscreens in a German university setting and evaluation of two popular cleaning methods using commercially available cleaning products

This article’s full text was made available for free on the publisher’s website at the time of writing this article.

References

1) Andersen, B. M., Rasch, M., Kvist, J., Tollefsen, T., Lukkassen, R., Sandvik, L., & Welo, A. (2009). Floor cleaning: effect on bacteria and organic materials in hospital rooms.Journal of Hospital Infection,71(1), 57-65.

2) Bergen, L. K., Meyer, M., Høg, M., Rubenhagen, B., & Andersen, L. P. (2009). Spread of bacteria on surfaces when cleaning with microfibre cloths.Journal of hospital infection,71(2), 132-137.

3) Gonzalez, E. A., Nandy, P., Lucas, A. D., & Hitchins, V. M. (2015). Ability of cleaning-disinfecting wipes to remove bacteria from medical device surfaces.American journal of infection control,43(12), 1331-1335.

4) Egert, M., Späth, K., Weik, K., Kunzelmann, H., Horn, C., Kohl, M., & Blessing, F. (2015). Bacteria on smartphone touchscreens in a German university setting and evaluation of two popular cleaning methods using commercially available cleaning products.Folia microbiologica,60(2), 159-164.

5) Gibson, K. E., Crandall, P. G., & Ricke, S. C. (2012). Removal and transfer of viruses on food contact surfaces by cleaning cloths.Appl. Environ. Microbiol.,78(9), 3037-3044.

6) Tuladhar, E., Hazeleger, W. C., Koopmans, M., Zwietering, M. H., Beumer, R. R., & Duizer, E. (2012). Residual viral and bacterial contamination of surfaces after cleaning and disinfection.Appl. Environ. Microbiol.,78(21), 7769-7775.

7) Barker, J., Vipond, I. B., & Bloomfield, S. F. (2004). Effects of cleaning and disinfection in reducing the spread of Norovirus contamination via environmental surfaces.Journal of hospital infection,58(1), 42-49.