Efficacy of Sanitizers, Disinfectants, and Sterilants in Cleanrooms and Healthcare

Cleanroom environments often require aggressive, if not extreme decontamination measures to ensure sterile-grade conditions that are needed for packaging, preparing, and compounding of sterile and non-sterile products.

The article explores the various types of chemical sterilants and disinfectants commonly used in cleanroom and healthcare environments. We will examine their classifications, efficacy, and the different types of antimicrobial agents employed. Additionally, we will discuss the additives used in sterilants and disinfectants, as well as provide a comprehensive list of cleanroom and healthcare disinfectants, sanitizers, and sterilants, along with their specific uses.

Chemicals can be hazardous if mishandled, and improper use can lead to adverse health effects or other risks. Users should be aware of any potential allergens, sensitivities, or specific precautions associated with the chemicals they are working with. It is crucial to use appropriate personal protective equipment (PPE) as recommended by the manufacturer and in accordance with relevant safety regulations.

Evaluating Efficacy of Sanitizers, Disinfectants, and Sterilants

Chemical sterilants are defined as chemicals that are used to destroy all forms of microbiological life. In cleanroom and healthcare settings, prototypical sterilizing agents include

• Steam under pressure, dry heat, EtO gas,
• Hydrogen peroxide gas plasma
• Liquid chemicals sterilizing agents

Unlike sanitizers and disinfectants, sterilants are designed for the complete eradication of microbial life, which is evaluated and measured by counting the number of colony-forming units (CFUs) present before and after sterilant use.

Contact Time: the duration for which a disinfectant or sterilization agent remains in direct contact with the surface or object being treated. It is the period during which the disinfectant or sterilant can exert its antimicrobial activity. Contact time is crucial for effective cleanroom disinfectant protocols, and ensures that the agent is allowed sufficient time to interact with and kill or deactivate microorganisms.

Log Reduction: In cleanroom and healthcare environments, log reductions, also known as logarithmic reductions, measure the effectiveness of a disinfection or sterilization process in reducing the number of microorganisms.

Sterility Assurance Level: Sterilization is measured and achieved via a sterility assurance level (SAL) of 10^-6, which means that for a population of 1,000 microbes, only 0.001 will remain after sterilization is complete.

By definition, chemical sterilants are required to achieve a 6-log reduction:

• 1-log reduction: 90% (10x) reduction in microbial populations
• 2-log reduction 99% reduction, (100x) reduction
• 3-log reduction: 99.9% reduction, (1,000x) reduction
• 4-Log Reduction: 99.99% reduction (10,000x) reduction
• 5-Log Reduction: 99.999% (100,000x) reduction
• 6-Log Reduction: 99.9999% (1,000,000x) reduction

Disinfectants that demonstrate a >5 log of E. coli within 30 seconds include:,

• Quaternary ammonium compounds
• Hypochlorite (1:10 dilution of 5.25% bleach)
• Ethanol

Disinfectants that demonstrate a >6 log of E. coli within 30 seconds include:

• Ethylene Oxide (EtO)
• Peracetic Acid (PAA)
• Hydrogen Peroxide Gas Plasma
• Chlorine Dioxide

Disinfectant Classifications in Healthcare

Low-level Disinfection: Destroys vegetative bacteria and some fungi and viruses but not mycobacteria or spores. Low-level disinfectants have widespread uses in cleanrooms for task-level wipedown of surfaces and equipment. In healthcare, low-level disinfectants offer as-needed decontamination of patient care items, shared devices, blood pressure cuffs, stethoscopes, and interior surfaces that are free of blood, bio-films, or bio-materials

• Effective for decontaminating Items that come in contact with the skin

Mid-Level Disinfectants: refers to the use of an agent that kills a wider range of pathogens than a low-level disinfectant but does not kill bacterial spores. Intermediate-level disinfection should be considered for environmental surfaces that are visibly contaminated with blood (texas.gov).

• Uses: Effective for decontaminating items that come in contact with mucous membranes or non-intact skin

High-level Disinfection is designed to eliminate or inactivate most micro-organisms, but does not necessarily ensure a complete microbiocidal result, nor renders a complete elimination of all microorganisms in or on an instrument, except for small numbers of bacterial spores. The FDA definition of high-level disinfection is a sterilant used for a shorter contact time to achieve a 6-log^10 kill within an appropriate and verifiable period of time.

Most high-level disinfectants include one or a combination of the following:

• Glutaraldehyde
• Hydrogen peroxide
• Ortho-phthalaldehyde
• Vaporized hydrogen peroxide
• Peracetic acid
• Quaternary Ammonia (also referred to as 'quats' or 'QACs)
• Sporicides (Kills spores)
• Germicides (Kills germs)
• Chemical Sterilants (Kills spores & germs)

Types of Anti-Microbial Agents

Sanitation and disinfection often vary in terms of frequency and scheduling. It can be beneficial in many industries to conduct everyday sanitation of surfaces and equipment, and weekly or monthly treatments with more aggressive disinfectants. For many cleanroom industries, sterilization procedures are typically conducted on longer schedule intervals that range from every week or month, or as little as quarterly or bi-annually. The frequency and totality of a decontamination program are largely determined by risk assessments, and standards set forth within each industry. Facilities may find it more approachable to conduct sporicidal or biocidal treatments in period cycles, rather than trying to tackle an end-to-end cleaning, disinfection, and sterilization procedure over a short period of time.

Biocides: Biocides refer to a broad category of chemical agents that are used to destroy, inhibit, or render harmless a wide range of microorganisms, including bacteria, viruses, fungi, algae, and protozoa. Biocides encompass various disinfectants, sanitizers, and antimicrobial agents. They are generally designed to reduce or eliminate the presence of harmful or unwanted microorganisms in various environments.

Sporicides: Sporicidal agents are specifically formulated to destroy or inactivate bacterial spores. Bacterial spores are highly resistant structures formed by certain bacteria that can survive harsh conditions and are more challenging to eliminate compared to vegetative cells. Sporicidal agents are required when the complete eradication of spores is necessary, such as in critical healthcare settings or when dealing with specific pathogens like Clostridium difficile.

Bactericides: Bactericides are disinfectants or antimicrobial agents specifically targeting bacteria. They are designed to kill or inhibit the growth of bacteria, preventing their reproduction and reducing their population. Bactericides can be broad-spectrum, effective against a wide range of bacteria, or narrow-spectrum, targeting specific types of bacteria.

Virucides: Virucides are agents specifically designed to inactivate or destroy viruses. They are formulated to target the structure and replication processes of viruses, preventing their infectivity.

Fungicides: Fungicides are used to kill or inhibit the growth of fungi or fungal spores. They are specifically formulated to control or prevent fungal infections or infestations.

Algaecides: Algaecides are agents that target and control the growth of algae. They are used to prevent or eliminate algae in various environments, such as swimming pools, water treatment systems, or outdoor surfaces.

Germicides: Germicide is a general term used to describe agents that kill or inhibit the growth of various microorganisms, including bacteria, viruses, fungi, and protozoa.

Sterilant and Disinfectant Additives

It's important to remember that cleaners, sanitizers, and disinfectants may include any number of secondary additives to enhance or alter the product in a way that can improve, stabilize, simplify, or extend the functionality of a product during transport, storage, and local use.

Facilities should evaluate primary and secondary ingredients to prevent unexpected chemical interactions that can affect the integrity of products and packaging. when a product and/or packaging is exposed to several chemical treatments cleaning, sanitation, and disinfection treatments over short periods of time.

Surfactants: Surfactants, or surface-active agents, are compounds that help reduce the surface tension of water and facilitate the removal of dirt, oils, and greases from surfaces. They aid in the cleaning action of the product.

Solvents: Solvents are substances that dissolve other materials and help in the removal of stains, oils, or residues. Common solvents used in cleaners include water, alcohol (such as isopropyl alcohol), and various organic solvents.

Disinfectants and antimicrobial agents: Disinfectants and antimicrobial agents are compounds that kill or inhibit the growth of microorganisms. Common disinfectants include chlorine compounds (e.g., sodium hypochlorite), hydrogen peroxide, quaternary ammonium compounds (QACs), phenols, and iodine-based compounds.

Stabilizers and pH adjusters: Stabilizers and pH adjusters are used to maintain the stability and pH of the product during storage and use. These ingredients ensure the product remains effective over time.

Denaturants: denaturants are chemical ingredients that are typically added to liquid-based alcohol sanitizers that taste foul and are intended to cause vomiting if the product were to be accidentally or intentionally consumed.

Fragrances: Scent-generating additives that make the formula more pleasant for the end user

Chelating agents: Chelating agents are chemicals that bind to metal ions and help prevent the negative effects of hard water minerals. They improve the effectiveness of surfactants and other cleaning agents.

Terra Universal Cleanrooms & Equipment

Terra aims to empower its customers with reasonable strategies to incorporate and enforce strict cleaning protocols that will benefit not only their employees, clients, and communities, but will also maximize the throughput of their operations.

The information provided in this article is intended for educational purposes only and should not be considered professional advice or guidance. It is crucial to exercise caution and adhere to proper safety protocols when handling and using chemicals, including sterilants, disinfectants, and sanitizers.

Need Assistance with Your Facilities Decontamination Programs?

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