For many of us...it's not hot. In fact in my part of Ontario our weather forecast reads something like this "A period of very cold wind chills is expected. A strong cold front has crossed southern Ontario ushering in much colder temperatures and gusty north winds. Wind chill values this afternoon have generally been between minus 20C (-4F) and minus 30C (-22F) across most of southern Ontario. Tonight will be very cold across all of southern Ontario. Although the winds will diminish somewhat, wind chills of minus 30C (-22F) to minus 35C (-31F) are expected tonight and into Friday morning."
That is bordering on "I'm going to call in sick" cold!
While not often thought of when choosing disinfectants, the temperature with which you're storing disinfectants should be considered. The truth is, extreme temperature fluctuations - be it extremely hot or, like today, EXTREMELY cold - can have a negative impact on disinfectants and/or disinfection itself. Most disinfectants are comprised of significant quantities of water. What does water do? It can boil. It can evaporate. And without a doubt, it can freeze. Aside from water, the chemicals within the disinfectant can be seriously impacted. They can degrade, which will impact both the stability or shelf life of the product, but more importantly it can impact the product's efficacy. Some can also combust! Both heating and freezing may also impact the stability of a product. Freezing can cause the solution to separate into different phases (think oil and water). If the solution is not homogenous, you do not have all ingredients mixed together which can lead to lack of efficacy.
Most disinfectant manufacturers will do a Freeze-Thaw test that determines what will happen if the product freezes. Generally about 5 Freeze-Thaw cycles are completed as the intent of this test is to determine what will happen if there is an accidental freezing during transportation or improper storage for a short period of time. The test is not intended to cover repeated freezing cycles, such as a product that is left in a car overnight in the cold for an extended period.
In terms of storage under high heat - Again, most disinfectants can handle such a situation for a short period of time, however, products such as bleach or ones with alcohol or solvents can be impacted significantly in terms of stability and efficacy if stored in extreme heat... say the trunk of a car or back of a tractor trailer.
The next time you get a call or email that goes something like this "....They carry wipes in their cars and dispense a few into a zip-lock baggie for each visit leaving the tub in their cars. Sometimes the tub stays in the vehicle all day and overnight. Does freezing (or heat in the summer) have any impact on the effectiveness of the wipes?" what will your answer be?
I hope you tell the person that storing disinfectants under high heat or extreme cold conditions will impact both the stability (shelf life) and efficacy of a product. If we're trying to stop the spread of infections we need to ensure our disinfectants work!
Please try to remember not to freeze your disinfectant and if you have some in your car right now... you may just want to run out and rescue it!