The Difference Between Enzymatic Cleaning and HOCl Disinfection

In a time when hygiene and disinfection are more important than ever, there is an increasing search for more effective methods to remove organic contamination, biofilm, and microorganisms. Various methods and agents are available for cleaning and disinfection, including enzymatic cleaning and disinfection with hypochlorous acid (HOCl).

How exactly do these methods work? What are the benefits? And how do these methods relate to each other?

Cleaning and Disinfection

Before delving deeper into the different methods, it is important to first understand the distinction between cleaning and disinfecting. Cleaning removes dirt and organic material, while disinfection neutralizes harmful microorganisms. More on this distinction can be found in a previously published blog.

Enzymatic Cleaning

As the name suggests, enzymatic cleaning works based on enzymes. These are proteins that can break down or convert specific substances. Different enzymes are added to cleaning agents, each with a different function. A commonly used type of enzyme is proteases, which help break down organic material. These enzymes degrade proteins, which make up a large portion of common dirt particles. Other types of enzymes can break down fats or starch, for example [1].

Enzyme-based cleaners are not disinfectants, as enzymes do not have bactericidal properties [1]. However, enzymatic cleaners can have an effect on biofilm. Biofilm consists of microorganisms and organic material that form a complex structure. It develops when different microorganisms adhere to a surface and connect through a self-produced extracellular polymeric substance (EPS). The EPS consists of proteins, polysaccharides, lipids, and extracellular DNA. With the right enzymes, these components can be broken down, loosening the biofilm structure and releasing microorganisms [2]. However, since enzymes cannot kill the released microorganisms, they can quickly reattach elsewhere. Additionally, biofilms often contain diverse microorganisms, making the EPS structure more complex and persistent. These structures are difficult to completely remove without a specific enzymatic composition. While standard enzyme-based cleaners cannot detach all microorganisms from a biofilm, they do loosen the EPS structure [3]. This makes it easier for a disinfectant to reach and eliminate the microorganisms [4].

Disinfection with HOCl

Enzymatic cleaning alone is not sufficient to completely remove microorganisms. The released microorganisms can reattach or cause contamination further along in the process. Therefore, disinfection remains necessary to kill the microorganisms [3]. This is achieved by disrupting the cell structures and metabolism of microorganisms. A highly effective agent for this is HOCl, which acts as a powerful oxidizer that kills bacteria, viruses, fungi, and yeasts [5]. It is produced sustainably and serves as an effective alternative to agents such as hydrogen peroxide and peracetic acid.

In biofilm, the EPS provides microorganisms with greater resistance to disinfectants. HOCl can penetrate and weaken the EPS, but it works much faster when enzymatic cleaning has already loosened the EPS structure. This allows HOCl to penetrate more deeply and fully eliminate microorganisms without first having to break down the biofilm [5,6]. This prevents microorganisms from regrowing and causing contamination.

Conclusion: The Relationship Between Enzymatic Cleaning and HOCl Disinfection

Because enzyme-based cleaners affect biofilm, some may mistakenly believe they serve as disinfectants. This is not the case, as they cannot kill microorganisms. Additionally, they are not capable of completely removing complex multi-bacterial biofilms. However, they are suitable for removing organic contamination and loosening the EPS of biofilms. As a result, they enhance the effectiveness of the disinfectant used afterward, allowing it to penetrate deeper into the biofilm [4].

By using an enzymatic cleaner first, followed by HOCl, biofilm can be tackled more effectively. This combination ensures:

• Thorough removal of organic contamination and elimination of microorganisms
• Effective breakdown of biofilm and prevention of recontamination
• Reduced risk of contamination and improved hygiene
• Less disruption of industrial processes
• A sustainable alternative to traditional disinfection methods

References

1. https://www.cdc.gov/infection-control/hcp/disinfection-sterilization/cleaning.html
2. Stiefel P, Mauerhofer S, Schneider J, Maniura-Weber K, Rosenberg U, Ren Q.2016.Enzymes Enhance Biofilm Removal Efficiency of Cleaners. Antimicrob Agents Chemother60:.https://doi.org/10.1128/aac.00400-16
3. Nahar, Shamsun & Mizan, Md & Ha, Angela & Ha, Sang-Do. (2018). Advances and Future Prospects of Enzyme-Based Biofilm Prevention Approaches in the Food Industry. Comprehensive Reviews in Food Science and Food Safety. 17. 10.1111/1541-4337.12382. 
4. Pant, K. J., Cotter, P. D., Wilkinson, M. G., & Sheehan, J. J. (2023). Towards sustainable Cleaning-in-Place (CIP) in dairy processing: Exploring enzyme-based approaches to cleaning in the Cheese industry. Comprehensive Reviews in Food Science and Food Safety, 22, 3602–3619. https://doi.org/10.1111/1541-4337.13206
5. Aherne, O., Ortiz, R., Fazli, M. M., & Davies, J. R. (2022). Effects of stabilized hypochlorous acid on oral biofilm bacteria. BMC oral health, 22(1), 415. https://doi.org/10.1186/s12903-022-02453-2
6. Cloete, T. E. The effect of anolyte and a combination of anolyte and catholyte on biofilms.