In commercial settings, chemical sterilants should always be handled and stored with care. Special protective equipment and environmental controls are required to protect workers from direct exposures, as well as environmental exposures that occur due to the presence of fumes, residuals on surfaces, or contaminated garments.

Alcohols

Isopropyl Alcohol (IPA) and Ethanol: Alcohols are most effective for deactivating a broad spectrum of bacteria and viruses when mixed at specific ratios of 70% - 90% alcohol combined with 10% - 30% water.

70% IPA is widely considered the most effective water-to-alcohol ratio for general sanitation and cleaning uses.

Appropriate water-to-alcohol ratios are important for alcohol disinfectants. Counter-intuitively, alcohol-water mixtures do not become more effective by increasing the percentage of alcohol content.

Alcohol and water-based disinfectants are most effective in 70% - 80% alcohol dilutions. Water content prevents the alcohol from evaporating too quickly, and ensures that the solution remains on the surface long enough for adequate contact time.

Alcohol-based disinfectants are considered low-level disinfectants, and should NOT be considered as replacements for strong, high-level disinfectants that can eradicate bacterial and fungal spores, or certain types of viruses in critical environments.

Aldehydes

Aldehydes, such as formaldehyde and glutaraldehyde, are considered powerful sterilants that can crosslink and disrupt proteins and nucleic acids in microorganisms, which inactivates and prevent the reproduction of bacteria, viruses, and spores.

Glutaraldehyde is a biocidal agent that results in the alkylation of sulfhydryl, hydroxyl, carboxyl, and amino groups of microorganisms, which alters RNA, DNA, and protein synthesis. Glutaraldehyde is common for healthcare applications due to its reliable activity in the presence of organic matter (20% bovine serum). Non-corrosive attributes make it well suited for the treatment of endoscopic equipment, thermometers, rubber, and other plastic equipment.

Ortho-phthalaldehyde (OPA): is an FDA-approved, high-level disinfectant with excellent microbicidal activity. However, OPA but was not effective against spores and gram-negative bacteria. It contains 0.55% 1,2-benzenedicarboxaldehyde (OPA), which is a clear, pale-blue liquid with a pH of 7.5. The CDC provides that OPA is particularly effective against certain zoonotic pathogens that infect humans, such as M. bovis. OPA renders a 6-log10 reduction for M. bovis using 0.21% OPA compared with 32 minutes using 1.5% glutaraldehyde

Advantages Ortho-Phthalaldehyde (OPA) Disinfectant:

  • Excellent stability over a wide pH range (pH 3–9), superior mycobactericidal activity (5-log10 reduction in 5 minutes) to glutaraldehyde.
  • Does not require exposure monitoring, minimal odor, and does not require activation
  • A viable alternative for glutaraldehyde in some applications,
  • Does not require elevated room temperature; suggested ambient temperature of 68ºF (20º C)

Disadvantages Ortho-Phthalaldehyde (OPA) Disinfectant:

  • Stains proteins (and skin) gray, handle with caution
  • Not sporicidal, not effective against gram-negative bacteria

Formaldehyde: is a chemical sterilant that offers broad activity in liquid and gas forms. Its typical applications Known for its pungent smell and distinctive odor, it can be diluted with water (formalin) or combined with alcohol for use in cleanrooms, healthcare, and surgical theaters.

Bleach | Chlorine | Hypochlorite Disinfectants

Hypochlorite refers to a chemical compound or an ion containing chlorine in the oxidation state of -1. It is commonly used as a disinfectant and bleaching agent due to its strong oxidizing properties. The most well-known hypochlorite compound is sodium hypochlorite (NaOCl), which is often used as a household bleach and in water treatment. Hypochlorite compounds

Bleach (NaOCl): refers to a solution of sodium hypochlorite (NaOCl) dissolved in water. Commercial bleach products usually contain a concentration of sodium hypochlorite ranging from 3% to 8.25%.

Sodium Hypochlorite (|NaClO): Sodium hypochlorite is the active ingredient in household bleach. It is effective against a broad spectrum of microorganisms and is commonly used as a disinfectant for surfaces, bucket mopping, water treatment, and laundering.

Chlorine is a chemical element with the symbol Cl. It is a highly reactive and strong oxidizing agent. At ~1 ppm, chlorine has been found effective in generating a 4-log reduction within 1 minute during suspension testing.

Bacteria within biofilms are up to 1,000 times more resistant to antimicrobials than are the same bacteria in suspension. Although new decontamination methods are being investigated for removing biofilms, chlorine and monochloramines can effectively inactivate biofilm bacteria.

Chlorine dioxide (ClO2): Chlorine dioxide is an inorganic compound that acts as a powerful disinfectant. It is used for water treatment, disinfection of surfaces, and as a fumigant.

Sodium Hydroxide (NaOH), also known as caustic soda or lye, is a highly caustic and strongly alkaline compound. It is an inorganic base that is commonly used in various industries and applications. In traditional formulations, NaOH is an essential ingredient for the soap-making process, which is generated by its interaction with fats and oils.

Hydrogen Peroxide

Hydrogen peroxide is one of the most widely used formulations for topical disinfection, emergency wound cleaning, and surface decontamination.

Hydrogen Peroxide Advantages:

  • Widely available, affordable
  • Effective for general household use to remove stains and sanitize surfaces
  • Eco-compatible for increasing oxygen levels and preventing root rot in plans and hydroponic systems

Hydrogen Peroxide Disadvantages

  • May cause damage to soft tissues when used for the treatment of cuts, scratches, and wounds
  • Can react with certain organic materials, such as wood, paper, or cotton, and potentially cause fires or explosions

Warning: Never mix Hydrogen Peroxide with other chemicals including bleach (chlorine gas), vinegar (highly corrosive peracetic acid), ammonia (chloramine or hydrazine gas), acids, or strong oxidizers

Peracetic Acid Sterilants

Peracetic acid is a strong oxidizing agent that can rapidly kill a broad spectrum of microorganisms. It disrupts microbial cell membranes and enzymes, leading to cell death. Peracetic Acid sterilants are used for a variety of cleanroom and healthcare applications cleaning and sanitizing reverse osmosis membranes and water distribution systems

In cleanrooms, PAA is among a short list of sterilants that can provide a 6-log reduction over a widespread area. Importantly, the chemical does not leave behind toxic by-products after dilution. Peracetic acid is considered ecologically friendly and breaks down naturally when diluted with water and will not leave behind toxic chemicals. Thus it can be disposed of in drains without requiring any special measures.

PAA & VHP Applications

  • Meat and poultry processing plants, canneries, dairies, breweries, wineries, soft drink plants, and agriculture
  • Peracetic acid sterilization system for endoscopes and devices that are sensitive to moisture and radiation

Radioactive Disinfection:

UV disinfection offers a unique method of decontamination that does not require heat, water, or aggressive chemicals that can damage sensitive devices.

Ultraviolet light is a radiological method of irradicating microbes from surfaces via 222-nm UV radiation (UV222), which is potentially a safer alternative to similar 254-nm UV radiation wavelengths.

UV light works in several methods to eliminate bacteria including:

  • Damaging the DNA by penetrating the cell wall and cytoplasmic membrane
  • Inhibiting replication via the formation of thymine dimers in bacterial DNA
  • Disruption and damage to ribosomes that are responsible for protein production

UVC Decontamination Applications

Germicidal UV lamps emit a specific wavelength of ultraviolet light that is highly effective in destroying the genetic material of microorganisms, rendering them incapable of reproduction or causing harm.

UV Sterilization-Filtration Cabinets simplify the routine disinfection of high-contact equipment or shared tools. The included HEPA filtration system and germicidal UV lamp reduce the presence of microorganisms and viruses such as microbes that increase HAI transmission. The cabinet features a timer for scheduling sterilization cycles, a door kill switch for preventing operators from UV exposure, and a mirror-finish stainless steel interior.

Vaporized Sterilants & Disinfectants

Vaporized hydrogen peroxide (VHP) or peracetic acid (PAA) is an aggressive and systemic method of disinfection and sterilization of widespread areas via chemical fogger.

Chemical foggers aerosolize and disperse extremely fine droplets into the air. After dispersion, the droplets will settle and deposit on surfaces, walls, ceilings, and furniture. Cold foggers, which deploy specialized formulations of cold sterilants, are commonly used for disinfection and sanitation purposes in cleanrooms, particularly in large spaces or cleanroom enclosures that require comprehensive coverage. Fogging is effective for the dispersion of disinfectant solutions and reaches surfaces, cracks, and crevices that would otherwise be difficult to reach with traditional cleaning methods.

  • PAA and VHP are powerful antimicrobial agents with broad-spectrum activity against bacteria, viruses, fungi, and spores.
  • VHP has several advantages: rapid cycle time (e.g. 30–45 min), low temperature, environmentally safe by-products (only water and oxygen), relatively good material compatibility and ease of operation, installation and monitoring.
  • Demonstrated effective and useful in healthcare to sterilize reusable metal and nonmetal devices used in healthcare facilities, and for fogging decontamination of intensive care units where severely ill and infectious patients are cared for

The downside of chemical foggers is that before fogging is applied, the room must already be cleaned and fully wiped down. Droplets that come into contact with debris, particulate, or biofilms on the surface will prevent the droplets from reaching surfaces underneath. Hence, chemical fogging is most specifically designed as a method of complete room sterilization and should be complementary to frequent wipe-down and disinfection routines.

PAA & VHP Fogger Limitations

  • PAA can cause corrosion of galvanized iron, steel, bronze, brass, and copper
  • Cleanroom fogger use requires evacuation of the immediate area but does not require the complete shutdown of the cleanroom HVAC system.
  • VHP is not compatible with standing liquids, powders, and cellulose materials
  • VHP of just 30 ppb can oxidize and ruin pharmaceuticals

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?

Terra Universal offers a wide selection of in-stock cleanroom cleaning products including total environments, waste receptacles, glove/garment dispensers, garment hampers, gowning furniture, and more. Many products are stocked and ready to ship in just 1 - 3 days from Terra's California facilities.

Contact a Terra specialist via phone, email, or start a live chat with a Terra specialist.