Disinfection (99.999% kill rate) is usually determined by applying a disinfectant for the recommended dwell time (usually 10 minutes for traditional products) so that it is effective in doing its job.  The best way of determining the dwell time is simply to read the label.  

In most cases, the dwell time means that the surface being disinfected should stay wet for the prescribed time in order to truly disinfect.  Some argue that once the product is applied, it can dry and still be working so read the label carefully to make sure that you are truly disinfecting which may require re-wetting the surface for the prescribed time.

Another issue to consider is that many disinfectants have a short shelf life once mixed with tap water from water sources containing chlorine, fluoride and many minerals.  Verify if the disinfectant from a mixing station degrades after 24 or 48 hours.  Also check to see if it is negatively affected by heat, light or other environmental stresses that could impact its efficacy resulting in less than satisfactory results.  

In some parts of the country, it may be a time to take a hard look at purchasing RTU (Ready to Use) disinfectants that are shipped in opaque bottles and usually have a much longer shelf life since they are mixed with distilled water under tight quality controls.  If you want to continue to use a mixing station, consider opaque bottles and dispose (safely) of any stale product once the product has expired.

Finally, make sure that all workers are trained properly in not only how to use the product but also why dwell time is necessary to protect users of areas being disinfected.  They need to buy into the reason for adequate dwell time since there will always be the temptation to cut corners by simply spraying and wiping which results in sanitizing (50% kill rate) at best.

As more and more pathogens come on line we need to reassess our disinfecting procedures so that our customers are getting the results we promised.  

Your comments and questions are important. I hope to hear from you soon. Until then, keep it clean.


Mickey Crowe has been involved in the industry for over 35 years.  He is a trainer, speaker and consultant. You can reach Mickey at 678.314.2171 or CTCG50@comcast.net.