Selecting the right preservative or biocide for your cleaning formulation can be challenging, especially with the limited lab capabilities for microbial testing at manufacturers of cleaning products and detergents. Several biocidal chemistries are available for cleaning formulations depending on the formulation specifications, application, product type, and level of preservation required.
This article will walk you through the preservation chemistries, whether offered in a single active biocide or a combination of two or more biocides.
Factors and formulation specifications that should be considered when selecting a biocide or preservative for a cleaner or a detergent are:
Biocides and preservatives are regulated by the EPA to be used only in the approved (tested) applications listed on the EPA label's direction of use section. Therefore, make sure that your product category, type, or application is approved/ mentioned in the label.
Finished product pH:
The performance of non-oxidizing biocides is typically dependent on the pH of the final product. Thus, it is vital to ensure that you are using the biocides within their stable pH range. Otherwise, the preservative will undergo rapid degradation and might see microbial growth or spoilage issues.
High temperatures can accelerate the breakdown of the biocides' active ingredient/s, especially if the temperature is higher than 40°C (≈ 100°F). If you are expecting poor storing conditions or exposure to high-temperature environments, you might need to choose a preservative with high-temperature stability.
Non-oxidizing biocides are widely used as preservatives due to their long-term stability and protection over long periods of storage with minimal degradation. Meanwhile, oxidizing biocides degrade quickly and might not protect the product throughout its lifetime.
However, most non-oxidizing preservatives are sensitive to the presence of strong oxidizing and reducing agents, including chlorine, ammonia, and more. Many preservatives are also incompatible with enzymes, which can result in a breakdown of the enzymes or the anti-microbial active. Therefore, it is important to check the compatibility of your formulation ingredients when selecting preservation candidates.
Microbial protection spectrum:
Most cleaning solutions need a bactericide for in-can protection. Various products may also need fungal or mold protection, especially if the product is slightly acidic. While some actives are effective against both types of microbes, dual active biocides would be a better option if a higher level of mold protection is required.
Microbial Chemistries and Actives:
We carry a broad array of products from DuPont that provide a wide range of protection based on the product and the formulation specifications. The following is an explanation of some of the main microbial control actives and biocides that can be used in cleaning solutions and detergents:
Chloro-methyl-isothiazolinone is one of the most commonly used actives in cleaning products due to its cost efficiency and long history of efficacy. It is also called Methylchloroisothiazolinone and abbreviated to CMIT, MCI, or CIT. The most common abbreviation is CMIT/MIT, as the product typically supplied in a 3-1 blend of CMIT and MIT.
CMIT is one of the most economically effective preservatives in the market due to its effectiveness at a low level of use. It is also supplied in aqueous solutions, making it easy to incorporate into the household and industrial formulations.
Yet, there are a couple of limitations to consider about Chloromethylisothiazolinone preservatives. The biocide is heat stable up to around 105°F (40°C). It also most effective at pH up to 8 or 8.5; otherwise, it will undergo some degradation and might need a higher dosage level.
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Methylisothiazolinone is a cost-effective biocide with improved stability in water-based products when the pH is higher than 8.5 or 9. The chemistry is effective at a low level of use and highly compatible with other actives. This active ingredient is commonly used in HI&I and personal care products.
MIT is widely used in combination with other actives, especially when the product is highly susceptible to microbial growth or needs protection against fungi or mold.
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Benzisothiazolinone or BIT is another isothiazolinone preservative developed to overcome stability concerns with CMIT. The chemistry is stable up to 300°F (150°C), providing increased processing flexibility in high-temperature systems and stability in tough storage and transportation conditions. It also offers excellent compatibility in most formulations with improved stability in the presence of amines.
BIT has a few limitations, including a slower kill rate and a performance gap against Pseudomonas. It can still be boosted by blending it with CMIT, Bronopol, DBNPA, and many other actives.
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Glutaraldehyde-based preservatives are used in various applications for their efficacy against both bacteria and mold at low concentrations. It is also one of the best options for laundry cleaners and detergents due to its compatibility, stability, and global approvals. Unlike many other preservatives, Glutaraldehyde tolerates high salt levels and is easily mixed into aqueous formulations.
Glutaraldehyde performance can be affected by the presence of amines and ammonia since its mode of action is to react with the amino acids in the microbes' cell wall. It is also incompatible with enzymes and biologically active compounds.
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Bronopol is one of the quick-acting biocides with high efficacy against bacteria, including Pseudomonas. It is also used to control slime forming bacteria and anaerobic organisms. Bronopol carries a broad range of FDA approvals for use in indirect food applications. Due to its quick action, it is commonly used in combination or dual active preservatives.
Still, the chemistry has some performance limitations for use as a preservative on its own. It is not very effective against fungi or mold; therefore, it is typically combined with CMIT when fungal protection is required. Bronopol can also be combined with BIT or Benzisothiazolinone for use in high pH systems.
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Biocidal actives are commonly combined for complementing the efficacy gaps or stability issues in certain conditions such as high temperatures and pH systems. The demand for combination preservatives is continuing to rise for extended product protection and the increased contamination levels in process waters and raw materials. Some examples of combination preservatives:
CMIT + BIT:
Provides protection against bacteria and efficacy against fungi while combining the quick action of CMIT with the long-term stability of BIT. DuPont offers BIOBAN™ BTCM based on CMIT and BIT combination.
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This combination offers protection against both bacteria and mold, especially in wipes and high pH cleaning solutions. DuPont offers BIOBAN™ 425 based on MIT and OIT combination.
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CMIT + Bronopol:
Boosted performance against bacteria with improved efficacy against Pseudomonas, slime forming bacteria, and anaerobic bacteria. DuPont offers ROCIMA™ 586 based on CMIT and Bronopol combination.
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BIT + Bronopol:
Provides protection against bacterial growth in high pH aqueous solutions and high-temperature systems or storage conditions. DuPont offers ROCIMA™ 607 based on BIT and Bronopol combination.
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If you are facing challenges with your products' microbial protection or are looking for a product recommendation, contact us, and one of our specialists will be in touch with you shortly. You can also click below to explore all our range of biocides and preservatives for cleaning products and detergents.