Sanitizers: Killers of the Unseen
There are numerous chemical methods to achieve sanitization of everything ranging from produce and meat, tables and chairs, and our drinking water. Anywhere you go you are affected by the use of sanitizers; however the misuse of sanitizers can be detrimental. It is important, therefore, to be aware of what types of sanitizers are being used and how to use them properly. The following is a review of three commonly used chemical sanitizers.
Chlorine is a very common, effective chemical for sanitizing because it is readily available in the form of bleach and inexpensive. With higher concentrations and contact times it can kill viruses including norovirus and has a disinfecting effect, while at lower concentrations it is safe to use on food contact surfaces. In its diluted form, chlorine follows the equilibrium equation HOCl + Cl ↔ H2O + Cl2. When testing its effective concentration as a sanitizer, it should be tested for the chlorine that is available to react with the targeted organisms: the available HOCl. This is why it is necessary to use free chlorine test strips, not total available chlorine test strips which responds to every chlorine molecule present whether it is free to sanitize or not. Another aspect that should be considered when chlorine is being used is its rapid degradation in the presence of high organic load. Therefore the surface to be sanitized must be first cleaned of organic matter so that then the chlorine can effectively sanitize the area.
QUAT is another common chemical used for sanitizing. Since QUAT can be made up of a variety of different combinations of ammonium chloride compounds it is also important to use the correctly calibrated test strips for the exact chemical that is being used. If a multi-QUAT chemical is being used, QT-40 or QAC-QR test strips should be used. If a single or dual chain QUAT is used, indicated by a makeup of one or two ammonium chlorides, a QT-10 test strip is appropriate. In the event that a chemical company has test strips specific to their own chemicals those should be used for the most accurate test. QUAT is significantly more resilient to organic load than chlorine, especially when utilizing a multi-QUAT variety. It also resists effects of pH much more so than chlorine. QUAT however does not degrade very rapidly, allowing it to be kept in solution for extended periods of time. It also leaves an antimicrobial film. This film provides a lasting effect continuously killing microorganisms, however it may inhibit desired bacterial activity in certain processes such as yogurt making or brewing.
Peracetic acid or Peroxyacetic acid is an environmentally friendly sanitizer which proves to be very effective in the presence of high organic load especially in comparison to chlorine. It is created by a combination of acetic acid and hydrogen peroxide, and degrades into the environmentally friendly products water, oxygen, and acetic acid. Because it is a relatively unstable chemical it is commonly stabilized with 1-hydroxyethylidene-1, 1-diphosphonic acid so it can be used longer after creation. Another advantage of using this sanitizer is it does not leave any film and is therefore preferred in some brewing processes. It does however need to be used in a well ventilated area because the acidic fumes the solution releases can cause irritation. It is also similar to chlorine in that it has corrosive activity and can start to break down equipment over time. However, if used properly it can be a very effective safe sanitizer.
This article serves as just a brief overview of a few commonly used chemical sanitizers however, there are many more in use today, and most likely many more to come. Education is the key to effective sanitizer use to ensure they are doing the job required, without undue side effects to the people using them.
Written by Nicole Reim, EHS