Disinfectants are used to kill and temporarily prevent the growth of bacteria, viruses and fungi. There are numerous types of disinfectants in the marketplace and just as many methods of application. Before detailing the types of disinfectants and the different methods to apply them, it is important to differentiate the meanings of the phrases “to clean", “to sanitize" and “to disinfect." It is critical for lab workers to understand this hierarchy of cleaning, sanitizing and disinfecting. Understanding the needed level of surface “clearing" helps you choose the correct product and also eliminates cross-contamination of experiments and also keeps the work environment a healthy one.

Cleaning vs. Sanitizing vs. Disinfecting

As previously noted, there are three levels of clearing the surfaces or instruments in your lab. These levels are cleaning, sanitizing and disinfecting. Cleaning a surface or instrument removes visible dust and debris. Cleaning does not remove microscopic organisms; it only clears away any visible elements such as dust or dirt. Sanitizing a surface or instrument makes that surface sanitary or free of elements that might hinder your experiment or even your health. Sanitizing is meant to reduce the occurrence and growth of bacteria, viruses and fungi. However, it is important to know that it is not meant to kill any of these microorganisms. The final level in the hierarchy is disinfecting. Disinfection is needed if the surface or instrument must be free and clear of all visible and microscopic organisms. Disinfecting a surface will “kill" the microscopic organisms as claimed on the label of a particular product.

Types of Disinfectants

There are thousands of disinfectants on the market and deciding which one to use may seem like a daunting task; however, there is a way to simplify this decision. All disinfectants can be classified into one of five groups based on the active ingredient used when manufacturing the product. 70% isopropyl alcohol is the standard active ingredient and it is widely available. The other active ingredients include phenolic, quaternary ammonium, sodium hypochlorite (or bleach) and peracetic acid. Each of these active ingredients has different levels of effectiveness as well as differences in what they actually kill. Be sure to carefully read the product label and any literature supplied by the manufacturer. It is very important to verify that the product you choose does, in fact, claim to “kill" the bacteria, virus or fungi you are attempting to eliminate. One level of effectiveness that is measured by OSHA is determining the disinfectant is effective against tuberculosis. If a disinfectant is proven effective against TB, which is one of the hardest organisms to kill, then OSHA considers the use of this product satisfactory when disinfecting areas with human blood and other organisms.

Applications

The application of disinfectant products is one of personal choice. Products come in concentrated form or ready-to-use. If you wish to control the dilution ratio then using a concentrate is a good idea. If you are not concerned with controlling the dilution ratio and just wish to utilize an effective product, then ready-to-use is easy and convenient. Disinfectants are available as a solution or as a wipe. Again, this is personal preference. Using a phenolic wipe is the same as using a phenolic solution.

Questions to Ask

There are two critical questions to ask yourself or your staff when disinfection is required in your work environment. First, what organism(s) do I need to “kill?" Secondly, which one of the five active ingredients is proven effective against that organism(s)? A third non-critical question to ask is, “What is my preferred method of applying the disinfectant: concentrated, ready-to-use, solution or wipe?

Mike Dunne is a Director of Marketing & Operations at Decon Labs – www.deconlabs.com – with more than 10 years experience working in the decontamination industry.