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Focus: effectiveness of cleaning products and disinfectants in a crèche
When there is no epidemic, the question of whether or not the use of disinfectant to clean early childhood centres (crèches) is appropriate or not frequently arises. The combined results of bacteriological and chemical analyses of several experimental studies have shown that the use of disinfectant once a week can remedy the failure to observe the daily practice of two-bucket mopping - which is officially recommended. However, users must ensure that the disinfectant does not have a toxic character for children.
This focus summarises the results of an experimental study which was carried out in 2014 to evaluate the necessity, if there is no epidemic, of using disinfectants for cleaning floors in early childhood centres. The study examined several floor cleaning procedures, some of which only used detergents, while others combined conventional cleaning products with disinfectants. In 2010 and 2011, similar experiments were carried out, each time at the same crèche at Uccle. However, the 2014 study took place at a crèche at Ixelles.
The studies are part of the missions of the Regional Cell for Intervention for Inside Pollution, or CRIPI. This cell is the result of a partnership between Brussels Environment (Department Laboratory, Air Quality), the Scientific Institute of Public Health (Department Health-Environment) and the Fund for Respiratory Diseases (FARES). The study was carried out in collaboration with the Office of Birth and Childhood (ONE).
Progress of the 2014 experimental study
Like in 2010 and 2011, the 2014 study had 2 aspects:
- a chemical aspect which consisted of checking for volatile organic compounds in the air which would likely be emitted by the products used;
- a biological aspect which made it possible to follow the evolution of the total bacteriological load on the floor.
The 2 products used during the study were:
- a concentrated liquid disinfectant detergent which cleans and disinfects all surfaces in a single process. This product, which is recommended in the food industry, was used in the crèche on a daily basis and will be referred to hereinafter as product "D3";
- a neutral detergent for floors, this is a concentrated product with low foaming, referred to hereinafter as product "N4".
The cleaning and/or disinfection took place every day around 6.00am.
The sampling progressed in 3 separate phases:
- An initial measuring campaign lasting 2 weeks, using disinfectant D3 every day = phase 1 (from 5 to 16 May 2014), followed by 2 weeks without taking any samples in order to proceed to the changing of the product;
- A second measuring campaign lasting 3 weeks, using conventional detergent N4 every day of the week = phase 2 (from 2 to 20 June 2014), followed by 1 week without taking any samples, to allow the introduction of disinfectant of D3 on the following Monday;
- A third measuring campaign lasting 3 weeks, using disinfectant D3 on the Monday and conventional detergent N4 on the other days of the week = phase 3 (from 30 June to 18 July 2014).
Regardless of the cleaning/disinfection procedure applied, it was apparent from the measurements that using a cleaning product or disinfectant results in a significant (although temporary) increase in the concentration of total VOCs. The concentrations measured at 9.00am were always higher than the concentrations measured at 5.00am, and the concentrations recorded at 2.00pm were always lower than those measured at 9.00am. However, the differences in the measured concentrations vary from one phase to another:
- The increase in concentrations of total VOCs was least pronounced during phase 1 of the experiments (the daily application of disinfectant D3).
- The daily application of neutral cleaner N4 (phase 2 of the experiments) resulted in higher concentrations of total VOCs, with an increase of around 50% at 2.00pm compared with the values recorded during phase 1. The unexplained presence of carbonates was also observed (ethyl methyl carbonates and diethyl carbonates), this time with a strong increase in concentrations at 9.00am, whereas the levels at 5.00am and 2.00pm remained stable.
- Phase 3, which was a combination of phases 1 (1 disinfection day in 5) and 2 (4 cleaning days out of 5), appears to be more difficult to interpret due to higher levels of VOC than during the first two phases. However, the results obtained tend to attribute the increase of VOCs observed during phase 2 to the use of the cleaner. The analysis of the carbonates also appears to be difficult to interpret, especially the high values recorded at 5.00am. During this phase, we can rule out the presence of supplementary sources which may have caused an increase in concentrations in VOCs, including carbonates.
Nevertheless, for all 3 phases, the concentrations obtained, whether of total VOCs or carbonates, were completely acceptable and did not pose any risk to health.
The first chart shows the total bacteria load present on the floor during all 3 phases. These were thermo-tolerant bacteria which develop at 37°C are considered to be primarily of human origin.
Bacteria load on the floor during the 3 phases: 2 weeks with disinfection (D3) every day, 3 weeks with only cleaning (N4) every day, and 3 weeks with disinfection (D3) on Monday, and cleaning (N4) on the other days.
C5, C25 … C95 correspond to percentiles.
We can observe that 50% of the measurements (the 50th percentile or median) did not exceed 49 to 59 CFU/25 cm², regardless of which floor cleaning procedure was used. For the higher percentiles, the lowest levels of contamination were during the phase with disinfection on the Monday and cleaning on the other days, whereas the phase with disinfection every day (phase 1), was found to be the least satisfactory, against all expectations.
Between the cleaning phase (phase 2), and the phase of disinfection on the Monday followed by cleaning on the other days of the week (phase 3), the disinfection phase appears to give slightly more satisfactory results. It is important to underline the fact that during these 2 phases, the practice of cleaning and/or disinfection with a different mop and the two-bucket technique (ONE recommendation) were rigorously applied every day.
The results of the experiments carried out in 2010 and 2011 have been included in the second chart. These results are quite similar or even slightly better than for the phase with disinfection one day of the week and cleaning on the following days, at least in the cases where the two-bucket mopping technique was rigorously applied every day.
Summary of the biological results of the 3 measuring campaigns 2010, 2011, 2014
In daily practice, the two-bucket technique could seem laborious, and might not be respected every day. The use of disinfectant once a week can compensate if this practice is not observed. Naturally this implies that the used disinfectant does not have a toxic character for children. The biological conclusions are also compatible with the chemical results, given that the combined use of the 2 products did not cause high concentrations of VOCs, and bearing in mind that the 2 carbonates do not have impacts on health in the range of concentrations measured.