Validity of Sanitizer Rotation
It has long been documented that bacteria/viruses/pathogens can develop resistance to antibiotics and create “super bugs." It may seem logical to assume bacteria and pathogens could develop a similar “resistance” to sanitizers, right? When we sanitize, we only are looking for a 5-log reduction in viable microbes…those that survive may be thought of as the “stronger” or “more resistant” bacteria. With only the remaining “survivors” left to replicate, this could impart sanitizer resistance to the bacteria. Or so one could assume.
There has been much literature published on this topic and the conclusions appear to lean towards the position where sanitizer rotation in a food plant manufacturing environment is not necessary.
The most significant reason is that we are dealing with two vastly different applications:
Antibiotics:
- Administered in relatively minute doses and typically work in conjunction with a person’s natural immune system
- Very specific bacterial cells and cell sites are targeted.
Sanitizers and Disinfectants:
- Applied at much higher (lethal) doses to inanimate non-porous food-contact surfaces
- Typically target many sites/structures/mechanisms of the bacterial cell – carpet bomb approach
One exception to note occurs with using quat-based sanitizers. The mode of action of quat sanitizers resembles that of an antibiotic rather than a disinfectant. Bacterial cells can demonstrate certain modes of action that can tamp down the effects of quat sanitizers. One mode is the use of efflux pumps (transfer proteins that traverse the cell wall) that remove contaminants (quats) from the cell. It should be noted, however, that this mainly can occur when the quat sanitizer is used at or below recommended use concentrations. When used at above minimum concentrations, the efflux pumps in the cell wall are overwhelmed, and the bacteria cell dies.
What is a likely cause for a perceived reduced efficacy of a particular sanitizer?
The main cause for a perceived or measured decrease in sanitizer efficacy is most likely due to inadequate sanitation practices and thoroughness of cleaning/scrubbing hard-to-reach surfaces in the processing facility: allowing harborage points and growth niches to develop. Inadequate soil removal can lead to biofilm formation. Biofilms can provide a protective barrier to bacteria that can make them orders of magnitude more resistant to sanitizers.
Final conclusion: There is little, if any, evidence that plant micro-organisms can or will develop a resistance to any sanitizing agent if it is applied in the proper concentration, for the required amount of time, to a surface that is visually clean and free of food residues. This is especially true with oxidizing sanitizers.
With all that said, there is a scenario where sanitizer rotation may be advantageous:
If the spectrum of microbes found in the plant is found to vary, sanitizer rotation may be advantageous. An example of this is a change in seasons where there may be elevated yeast and mold counts (during planting and/or harvesting season). If a plant normally uses an acid-anionic-type sanitizer as their normal environmental sanitizer, they may want to consider switching to an oxidizing sanitizer during those times of the year. Oxidizing sanitizers such as chlorine or peroxide/PAA are more efficacious against yeasts and molds compared to acid-anionic sanitizers.
Reach out to The RITE Team® for more information on selecting and using sanitizers in your facility.
