Typically, a research piece about botulism would fall outside of the scope of topics we cover, but with this most recent article's focus on vacuum cleaners and the suggestion that they maybe be potential vectors for disease (like botulism), we found this noteworthy. Yes, you read that right, a possible link between your vacuum cleaner and botulism. Most people think of vacuums as a tool to get rid of carpet frizz, dust, pet hair, stale crumbs under the coffee table, and the occasional gummy worm. They leave our carpets refreshed and clean feeling, and hardwood floors walkable for the bare feet again. But what we can't see or feel is what Caroline Duchaine and her research team from the Queensland University of Technology and Laval University wanted to study.

Vacuum cleaners can release large concentrations of particles, both in their exhaust air and from resuspension of settled dust (Duchaine et al. 2013). The aim of this study was to evaluate particles emitted into the air from various vacuum cleaners. Tests and measurements were made based on dust inside dust bags or dust bins (some were bagless) and from air emitted from the machine while in use. Duchaine and her team quantified how much bacteria and mold could be found within these tests with a particular focus on Clostridium botulinum, Salmonella spp and Penicillium/Aspergillus. While Salmonella is fairly commonly known, the other two are related to botulism and mold, respectively. For infants/toddlers and those with allergies or compromised immunity, this study can be somewhat worrisome.

There have been previous studies on vacuum cleaners that have established that dust bags can be a reservoir for certain types of microbes, and in one particular instance during the 1950's vacuums have gotten attention for this, as a dust bag was the sole source of a Salmonella outbreak amongst infants in a hospital ward.

Before, you toss your vacuum, consider some of the findings on this study. No appreciable levels of the microorganisms, with the exception of mold spores (which varied more widely in terms of measurable amounts), was found in the emissions. While there were some present, the concentration was extremely low. In the dust bag though, the story was a bit different. Concentrations of the different microbes found were fairly consistent, regardless of brand (of vacuum), and this leads researchers to believe that ‘vacuum emissions could potentially lead to short and more intense bioaerosol exposures than those due to resuspension of settled dust’ given the emission rate of most vacuums.

At this point, it is likely worth noting a couple things. First, brands of the vacuum cleaners used were not disclosed. The near two dozen units were collected from the homes of staff and students at the university. The age of the vacuums tested ranged 6 months to 22 years and the prices from $75 to $800 (AUD – Australian), and each vacuum was tested as it arrived. Additionally, samples could not be obtained from all the units involved. A little over half of the models tested produced measurable results, in terms of emissions and dust bag content. The next thing to keep in mind is this. For test purposes, researchers used HEPA filter air through the vacuums, to ensure uniformity but also to introduce as pure of a medium as possible.

This was an interesting research topic, since dust is often overlooked as a conglomerate of debris with no life or benefit. But here we have live microorganisms amongst nonliving material. This could also shed some light onto what kind of vacuum do you want to purchase. If this blog has got you thinking about switching your vacuum to something a little more vacuum sealed, here are few things to consider.

Filtration matters – The fact that researchers used HEPA filtered air in their tests is telling, particularly when you compare it to the size of some of the microbes examined. Mold spores typically range in size from 3 to 40 microns while Clostridium botulinum, a rod-shaped microbe, can be .5-2 microns wide by 1.6 to 22 microns long. Certified HEPA filters capture 99.97% of particles 0.3 microns and larger.

Vacuums With a Bag Should Be Better – The entire point of the research piece was to focus on bioaerosols that vacuums can create and emit throughout the home. What is the point of trapping microbes only to expose yourself to them when you empty the dust bin?

Particularly Sensitive Groups, Pay Heed to What You Clean With – You often get what you pay for, and not all vacuums marketed as ‘HEPA’ are equal. Some have been independently tested and certified (like Miele or Dyson), and other haven't. Even if you decide to pay for a vacuum with high end filtration, you are likely selling yourself short if you then use cheaper, aftermarket replacement dust bags or filters.

Lastly, On the Microscopic Level, Seals Matter – Vacuums that features seals to prevent air leakage and those that have dust bags that seal when you go to remove them are going to be advantageous.

Although this research does shed some light on potential bacterial exposure, don't fret because these types of infections are very rare. Overall, this statement from the study says a lot, ‘The vacuum characteristics here are likely to be the main predictor of emission, rather than dust content.’ However, if you're in a position where you have to crash on the floor at a friends or grandmas… you may want to consider a blowup mattress!

To read the full research article.

Author: R. Power