I was at a conference earlier in the year and listened to a fascinating presentation on “the perfect disinfectant”.
The presenter was a distinguished and tenured university Professor in the USA, and was almost wondering out aloud what the issues were for a perfect disinfectant?
The USA Environmental Protection Agency had a number of senior staff present for the discussion and they were very keen recipients of the information being presented on this topic.
So what is the perfect disinfectant, and is it sustainable? Logically the perfect disinfectant will be completely biodegradable or environmentally neutral, will not damage people, and will not damage the surfaces or objects on which it is used. The perfect disinfectant will water soluble and water compatible.
In fact, water itself is a good start. It is not toxic. It doesn’t stimulate antimicrobial resistance either. And then there is salt. Very common and if separated chemically into its charged components then it too is sustainable.
Another goal is to create a disinfectant that would be sufficiently selective. The perfect product would kill the bad bugs while preserving the not so bad bugs. The really nasty super bugs would die, or they would be stimulated to become less nasty, and perhaps even revert to a friendly status.
I felt like I was being called into a microbial love fest, and that I would also get the infection.
The looming loss of Antibiotics that actually work was a technical backdrop for the meeting. And while the focus was really on sick buildings, there was as much concern for the “chemicals” that might make people sick, as much as for the microbes that really do kill people.
Whereas the setting for the conference was household products, given that MRSA, VRE, CRE and C.diff are all moving around within the healthy community, I wondered about the underlying point. Where is the balance between the trade-off of disinfectant efficacy and Health, Safety and Environmental (HSE) issues?
So, when it was my time to present I introduced some lessons on the hard edge of disinfectants. These five lessons are worth repeating so that we all understand the context of disinfectant use:
- Only use a disinfectant when it is appropriate for hygiene reasons;
- When you do use a disinfectant, choose one that works and that will kill the bugs of concern in the context of the use. But use an appropriate disinfectant and not just the “strongest”;
- Only use disinfectants (in Australia) that are registered with the TGA;
- Use the disinfectant at the recommended conditions, such as temperature and dilution; and
- ALWAYS clean first. Sometimes that will mean you might use the disinfectant twice (once to provide initial cleaning, and then again for actual disinfection).
Here is the thing to remember with a disinfectant. It is meant to kill micro-organisms. It is meant to be reactive and dangerous to microbes. The most significant sustainability aspect with disinfectant usage is to keep people alive with a clean and hygienic environment while killing all the bugs. Read the label and the Safety Data Sheet to ensure that unintended health and environmental effects do not occur through incorrect use or disposal.
And remember – the bugs are trying to survive. They will hide, they will resist and develop resistance even they are not all dead. The worst outcome can be a sub lethal dose, which allows survivors, and then evolution takes over (survival of the fittest).
Water is a fabulous disinfectant, but only when it is really hot – hot enough to scald – and so even water poses a risk as a disinfectant. Like all disinfectants, you must consider the weaknesses, as well as the strengths.
The sustainable lesson on disinfectants is that these products are intended to disrupt the environment, albeit only locally, and albeit only temporarily. So, choose your disinfectant wisely, and use it well, and we will all have a more healthy and sustainable world.
This first appeared in the September/October issue of INCLEAN Magazine.