Decontamination of work surfaces is essential to prevent researcher exposure and contamination of experiments. All material taken out of a biological lab should be surface decontaminated before leaving the lab. Decontamination reduces the microbial contamination of materials or surfaces and is accomplished through the use of a chemical disinfectant.
Disinfection refers to the elimination of virtually all pathogenic organisms on inanimate objects and surfaces thereby reducing the level of microbial contamination to an acceptably safe level. Disinfection is accomplished through the use of chemical disinfectants.
In contrast, sterilization refers to the destruction of all microbial life. This is typically accomplished with heat and steam through autoclaving.
Chemical disinfectants will vary in their effectiveness. Choosing an appropriate disinfectant will depend on a number of factors such as:
- The type of organism you are handling
- The item to be disinfected
- The nature of the disinfectant – cost, ease of use, shelf life, contact time, and personal protective equipment
Below are the steps to keep in mind while selecting a disinfectant:
- Is it a bacteria, virus, fungus, or protozoa?
- Does it form fungal or bacterial spores?
- If it’s a virus, is it enveloped or non-enveloped?
- Pure cultures are easy to identify, but for animal, human, or environmental samples, consider what organisms are likely to be present.
- Bacteria and enveloped viruses are generally more susceptible to disinfection
- Spore formers are more resistant
- Bleach is effective against most organisms at the appropriate concentration and contact time
The table below shows disinfectant general effectiveness based on disinfectant type:
| Organism classification (in increasing hardiness) |
Susceptible to | Moderately susceptible to | Resistant to |
|---|---|---|---|
| Enveloped Viruses (HIV) Gram positive bacteria Large non-enveloped viruses (adenovirus) Vegetative fungi and algae Gram negative bacteria |
Bleach, peroxide, quaternary ammonium (quats), alcohol, phenolics, aldehydes | – | – |
| Fungal spores | Bleach, peroxide, quats, aldehydes | alcohol, phenolics, | – |
| Protozoal cysts (Giardia) | Bleach, peroxide, aldehydes | Alcohol, phenolics | Quats |
| Small, non-enveloped viruses (parvovirus, hepatitis B virus) | Bleach, peroxide, aldehydes, some quats | Phenolics | Alcohol, some quats |
| Mycobacterium tuberculosis | Bleach, peroxide, aldehydes, some quats | Phenolics | Alcohol, some quats |
| Helminth eggs (Ascaris) | Bleach, peroxide, aldehydes | – | Alcohol, quats, phenolics |
| Protozoal oocysts (cryptosporidium) | Bleach, peroxide, aldehydes | – | Alcohol, quats, phenolics |
| Bacterial spores | – | Bleach, peroxide, aldehydes | Alcohol, quats, phenolics |
Liquid Waste Decontamination
Learn more about Liquid Waste Disposal
- Add concentrated disinfectant
- Household bleach (5.25% or greater concentration of sodium hypochlorite) to a 10% final concentration
- Wescodyne to a 1-1.6% final concentration
- Clorox regular or Clorox germicidal bleach is recommended
- Do not use laundry bleach
- Contact Biosafety for other options if bleach cannot be used
Spill Cleanup
- Make a fresh dilution of 10% final concentration of household bleach (5% or greater concentration of sodium hypochlorite)
- Bleach must be fresh as dilute bleach loses effectiveness after 1-2 weeks
- Clorox regular or Clorox germicidal bleach is recommended
Surface or Tool/Equipment Decontamination
- Consider contact time – shorter is recommended
- Consider the type of material you’re decontaminating – some products like bleach are corrosive and may require a rinse or flush step when used with certain surfaces (i.e. stainless steel)
- PREempt is a broadly effective product with a shorter contact time and is non-corrosive (see below for details)
Work With Human Materials
- 70% ethanol is not appropriate for surface decontamination
- OSHA requires a disinfectant that is effective against Tuberculosis or both HIV and Hepatitis B
- 10% household bleach
- Any of the products listed on the Disinfectant Cost and Shelf Life tables below
- FDA sterilants
EPA registration numbers will confirm whether the product is appropriate (EPA Lists B or D). See Disinfectants Appropriate for Use with Human Material section below
Once you’ve determined what types of disinfectants are effective for your organism and application, there are some other factors to consider:
Contact time is a measure of how long the disinfectant must remain in contact with the material or surface to ensure proper disinfection.
- Contact time will vary depending on the product and organism targeted
- Some products require 10 minutes contact
- Newer quaternary ammonium products (quats) and some active hydrogen peroxide products are effective in 5 minutes or less
- Alcohols can evaporate too quickly to achieve sufficient contact time
The following chart lists some commonly used disinfectants and their required contact time:
| Disinfectant Brand | Disinfectant Category | Contact time (in minutes) | ||||
|---|---|---|---|---|---|---|
| Bactericidal | Virucidal | Tubercucidal | Fungicidal | Bacterial Sporicidal | ||
| PREempt | Activated peroxide | 1 | 1 | 5 | 10 | – |
| 10% Chlorox bleach | Chlorine | 10 | 10 | 10 | 10 | 10 |
| Bleach-rite spray | Chlorine | 1 | 1 | 1 | 2 | 5 |
| Quatricide TB | Quat | 3 | 10 | 5 | 10 | – |
| Sklar | Quat | 2 | 2 | 2 | 2 | – |
| Lysol professional spray | Quat | 10 | 10 | 10 | 10 | – |
| Lysol I. C. | Quat | 10 | 10 | – | 10 | – |
| 1% Wescodyne | Iodophor | 10 | 10 | 10 | 10 | – |
| Clidox | Aldehyde | 5 | 5 | 5 | 5 | 300 |
| Sporicidin | Phenolic | 10 | 5 | 10 | 10 | – |
| Peridox | Peroxide/acid | 2 | 2 | 5 | 1 | 3 |
Shelf life refers to how long disinfectants remain effective. This is noted by the product’s expiration date. Cost refers to the price of the disinfectant, which can vary greatly.
- Shelf life can vary greatly by product
- Concentrated products that require dilution generally lose effectiveness faster once diluted as compared to ready-to-use (RTU) products
- RTU products include stabilizers and generally remain effective longer
- Always check product labels and be aware of the expiration date of your disinfectant
- Concentrated products generally cost less than ready-to-use products but require more preparation time
- Ready-to-use products are more expensive but do not require valuable research time in measuring and diluting
- Buying in bulk can reduce cost
The following chart lists disinfectants in common use at MIT and their approximate price and shelf life:
Average Cost and Shelf Life of Disinfectants
| Disinfectant | Average Cost/Quart | Shelf Life |
|---|---|---|
| PREempt RTU Spray | $7.35 | 3 years |
| Lysol IC Spray | $18.81 | 2 years |
| Lysol Professional Spray | $12.58 | 2 years |
| Quatricide TB Spray | $3.66 | 1 year |
| Sklar disinfectant | $10.34 | 3 years |
| Sporicidin | $11.80 | 4 years |
| Peridox RTU | $25.86 | 1 year |
Average Cost and Shelf Life of Concentrated Disinfectants
| Disinfectant | Average Cost/Quart | Shelf Life of Concentrate | Shelf Life of Dilution |
|---|---|---|---|
| PREempt | $0.57 | 3 years | 10-90 days |
| Lysol IC | $0.05 | 2 years | 1 year |
| Quatricide | $0.09 | 1 year | 2 months |
| Quatricide PV-15 | $0.03 | 1 year | 2 months |
| Clorox Germicidal Bleach | $0.17 | 1 year | 2 weeks |
How to tell if your disinfectant has expired?
Some disinfectants lists the expiration date clearly
Most disinfectants will have a production code that uses a Julian date to indicate when the product was made. Typically, you see 1-2 digits followed by the Julian date.
This example of Lysol IC shows:
15 = year= 2015
162 = 162nd day of the year = June 11
It was manufactured on June 11, 2015.
From the table above we can see that the shelf life for Lysol IC Concentrate is two years. Therefore this product expired in 2017.
Obtaining the Disinfectant
- Most common products are available in the VWR stockroom (including concentrated bleach and PREempt).
- Most products are available through B2P; check all entries as some vendors charge more for the same product
- For some specialized products, it may be necessary to order directly from the vendor; contact Biosafety if you have questions
Due to the nature of the active ingredient, some disinfects pose a chemical hazard and may require additional PPE:
- Some aldehydes (Clidox), phenolics (Sporicidin), and blended activated hydrogen peroxide & acid products (Peridox) require special PPE
- Always consult the product label and SDS prior to using a disinfectant
- If possible, select a less hazardous product
- Most of these products are used to inactivate bacterial spores
Some disinfectants can leave a residue or produce an unpleasant odor:
- Bleach and some quats can leave residue
- Iodophors can stain
- Phenolics can have a strong, unpleasant odor
- Activated hydrogen peroxide can leave a slight residue that easily removed with water or alcohol
- Alcohols leave no residue
Some products may come in a concentrated form where the user has to dilute it before use. Others come in a ready-to-use (RTU) form:
- RTU products can be more expensive upfront, but require no preparation time (cost savings = reduced researcher prep time)
- RTU usually contain stabilizers and tend to last longer than diluted products
- Concentrated products can be more cost-effective upfront but require more researcher preparation time
- Disinfectants diluted from concentrate must be replaced on a more frequent basis and require more monitoring to avoid using expired dilutions
There are seven broad categories of disinfectants. Each has different benefits and limitations:
| Type | Properties | Limitations |
|---|---|---|
| Activated Hydrogen Peroxide (AHP) |
|
|
| Alcohols |
|
|
| Aldehydes |
|
|
| Chlorine (bleach) |
|
|
| Iodophors |
|
|
| Quaternary ammonium compounds (quats) |
|
|
| Phenolics |
|
|
The OSHA Bloodborne Pathogen Standard is designed to protect workers from exposure to Bloodborne Pathogens, including but not limited to HIV, Hepatitis B, and Hepatitis C. It requires that work surfaces that are contaminated with blood or other potentially infectious material (anything from the human body, including human cell lines) or that have the potential to have become contaminated during the course of work be decontaminated with an appropriate disinfectant.
Any lab that works with human material must use an appropriate disinfectant to disinfect work surfaces or to decontaminate surfaces and equipment after a spill. Currently, OSHA recognizes the following as appropriate disinfectants:
- EPA-registered tuberculocidal disinfectants (EPA-registered list B)
- EPA-registered disinfectants that are labelled as effect against both HIV and Hepatitis B (EPA-registered list D)
- Diluted bleach solutions (10% or greater dilution of household bleach which equates to 0.5% or greater sodium hypochlorite)
- Sterilants/High-Level Disinfectants cleared by the FDA (Note: most researchers don’t use these products)
- Please note that 70% ethanol is not recognized as an appropriate surface disinfectant by OSHA. Evaporation of the alcohol prevents sufficient contact time to inactivate Hepatitis B
To check if your product meets the OSHA requirements:
- Locate the EPA registration number found on the product label of your disinfectant
- Go to the appropriate EPA list using the links above
- Search the list using the first two sets of numbers in the EPA registration number
- For example, if your product label lists the EPA registration number as 777-99-675, search the list for 777-99 (omit 675 from your search)
The last number is the distributor identification number. These will not be included on the EPA lists since only the initial formulation submitted to the EPA is listed.
If the EPA registration number appears on one of these lists, the disinfectant is appropriate to disinfect surfaces where human blood or material has been handled.
Learn more about Bloodborne Pathogens
Decontamination of work surfaces is essential to prevent researcher exposure and contamination of experiments. All material taken out of a biological lab should be surface decontaminated before leaving the lab. Decontamination reduces the microbial contamination of materials or surfaces and is accomplished through the use of a chemical disinfectant.
Disinfection refers to the elimination of virtually all pathogenic organisms on inanimate objects and surfaces thereby reducing the level of microbial contamination to an acceptably safe level. Disinfection is accomplished through the use of chemical disinfectants.
In contrast, sterilization refers to the destruction of all microbial life. This is typically accomplished with heat and steam through autoclaving.
Chemical disinfectants will vary in their effectiveness. Choosing an appropriate disinfectant will depend on a number of factors such as:
- The type of organism you are handling
- The item to be disinfected
- The nature of the disinfectant – cost, ease of use, shelf life, contact time, and personal protective equipment
Below are the steps to keep in mind while selecting a disinfectant:
- Is it a bacteria, virus, fungus, or protozoa?
- Does it form fungal or bacterial spores?
- If it’s a virus, is it enveloped or non-enveloped?
- Pure cultures are easy to identify, but for animal, human, or environmental samples, consider what organisms are likely to be present.
- Bacteria and enveloped viruses are generally more susceptible to disinfection
- Spore formers are more resistant
- Bleach is effective against most organisms at the appropriate concentration and contact time
The table below shows disinfectant general effectiveness based on disinfectant type:
| Organism classification (in increasing hardiness) |
Susceptible to | Moderately susceptible to | Resistant to |
|---|---|---|---|
| Enveloped Viruses (HIV) Gram positive bacteria Large non-enveloped viruses (adenovirus) Vegetative fungi and algae Gram negative bacteria |
Bleach, peroxide, quaternary ammonium (quats), alcohol, phenolics, aldehydes | – | – |
| Fungal spores | Bleach, peroxide, quats, aldehydes | alcohol, phenolics, | – |
| Protozoal cysts (Giardia) | Bleach, peroxide, aldehydes | Alcohol, phenolics | Quats |
| Small, non-enveloped viruses (parvovirus, hepatitis B virus) | Bleach, peroxide, aldehydes, some quats | Phenolics | Alcohol, some quats |
| Mycobacterium tuberculosis | Bleach, peroxide, aldehydes, some quats | Phenolics | Alcohol, some quats |
| Helminth eggs (Ascaris) | Bleach, peroxide, aldehydes | – | Alcohol, quats, phenolics |
| Protozoal oocysts (cryptosporidium) | Bleach, peroxide, aldehydes | – | Alcohol, quats, phenolics |
| Bacterial spores | – | Bleach, peroxide, aldehydes | Alcohol, quats, phenolics |
Liquid Waste Decontamination
Learn more about Liquid Waste Disposal
- Add concentrated disinfectant
- Household bleach (5.25% or greater concentration of sodium hypochlorite) to a 10% final concentration
- Wescodyne to a 1-1.6% final concentration
- Clorox regular or Clorox germicidal bleach is recommended
- Do not use laundry bleach
- Contact Biosafety for other options if bleach cannot be used
Spill Cleanup
- Make a fresh dilution of 10% final concentration of household bleach (5% or greater concentration of sodium hypochlorite)
- Bleach must be fresh as dilute bleach loses effectiveness after 1-2 weeks
- Clorox regular or Clorox germicidal bleach is recommended
Surface or Tool/Equipment Decontamination
- Consider contact time – shorter is recommended
- Consider the type of material you’re decontaminating – some products like bleach are corrosive and may require a rinse or flush step when used with certain surfaces (i.e. stainless steel)
- PREempt is a broadly effective product with a shorter contact time and is non-corrosive (see below for details)
Work With Human Materials
- 70% ethanol is not appropriate for surface decontamination
- OSHA requires a disinfectant that is effective against Tuberculosis or both HIV and Hepatitis B
- 10% household bleach
- Any of the products listed on the Disinfectant Cost and Shelf Life tables below
- FDA sterilants
EPA registration numbers will confirm whether the product is appropriate (EPA Lists B or D). See Disinfectants Appropriate for Use with Human Material section below
Once you’ve determined what types of disinfectants are effective for your organism and application, there are some other factors to consider:
Contact time is a measure of how long the disinfectant must remain in contact with the material or surface to ensure proper disinfection.
- Contact time will vary depending on the product and organism targeted
- Some products require 10 minutes contact
- Newer quaternary ammonium products (quats) and some active hydrogen peroxide products are effective in 5 minutes or less
- Alcohols can evaporate too quickly to achieve sufficient contact time
The following chart lists some commonly used disinfectants and their required contact time:
| Disinfectant Brand | Disinfectant Category | Contact time (in minutes) | ||||
|---|---|---|---|---|---|---|
| Bactericidal | Virucidal | Tubercucidal | Fungicidal | Bacterial Sporicidal | ||
| PREempt | Activated peroxide | 1 | 1 | 5 | 10 | – |
| 10% Chlorox bleach | Chlorine | 10 | 10 | 10 | 10 | 10 |
| Bleach-rite spray | Chlorine | 1 | 1 | 1 | 2 | 5 |
| Quatricide TB | Quat | 3 | 10 | 5 | 10 | – |
| Sklar | Quat | 2 | 2 | 2 | 2 | – |
| Lysol professional spray | Quat | 10 | 10 | 10 | 10 | – |
| Lysol I. C. | Quat | 10 | 10 | – | 10 | – |
| 1% Wescodyne | Iodophor | 10 | 10 | 10 | 10 | – |
| Clidox | Aldehyde | 5 | 5 | 5 | 5 | 300 |
| Sporicidin | Phenolic | 10 | 5 | 10 | 10 | – |
| Peridox | Peroxide/acid | 2 | 2 | 5 | 1 | 3 |
Shelf life refers to how long disinfectants remain effective. This is noted by the product’s expiration date. Cost refers to the price of the disinfectant, which can vary greatly.
- Shelf life can vary greatly by product
- Concentrated products that require dilution generally lose effectiveness faster once diluted as compared to ready-to-use (RTU) products
- RTU products include stabilizers and generally remain effective longer
- Always check product labels and be aware of the expiration date of your disinfectant
- Concentrated products generally cost less than ready-to-use products but require more preparation time
- Ready-to-use products are more expensive but do not require valuable research time in measuring and diluting
- Buying in bulk can reduce cost
The following chart lists disinfectants in common use at MIT and their approximate price and shelf life:
Average Cost and Shelf Life of Disinfectants
| Disinfectant | Average Cost/Quart | Shelf Life |
|---|---|---|
| PREempt RTU Spray | $7.35 | 3 years |
| Lysol IC Spray | $18.81 | 2 years |
| Lysol Professional Spray | $12.58 | 2 years |
| Quatricide TB Spray | $3.66 | 1 year |
| Sklar disinfectant | $10.34 | 3 years |
| Sporicidin | $11.80 | 4 years |
| Peridox RTU | $25.86 | 1 year |
Average Cost and Shelf Life of Concentrated Disinfectants
| Disinfectant | Average Cost/Quart | Shelf Life of Concentrate | Shelf Life of Dilution |
|---|---|---|---|
| PREempt | $0.57 | 3 years | 10-90 days |
| Lysol IC | $0.05 | 2 years | 1 year |
| Quatricide | $0.09 | 1 year | 2 months |
| Quatricide PV-15 | $0.03 | 1 year | 2 months |
| Clorox Germicidal Bleach | $0.17 | 1 year | 2 weeks |
How to tell if your disinfectant has expired?
Some disinfectants lists the expiration date clearly
Most disinfectants will have a production code that uses a Julian date to indicate when the product was made. Typically, you see 1-2 digits followed by the Julian date.
This example of Lysol IC shows:
15 = year= 2015
162 = 162nd day of the year = June 11
It was manufactured on June 11, 2015.
From the table above we can see that the shelf life for Lysol IC Concentrate is two years. Therefore this product expired in 2017.
Obtaining the Disinfectant
- Most common products are available in the VWR stockroom (including concentrated bleach and PREempt).
- Most products are available through B2P; check all entries as some vendors charge more for the same product
- For some specialized products, it may be necessary to order directly from the vendor; contact Biosafety if you have questions
Due to the nature of the active ingredient, some disinfects pose a chemical hazard and may require additional PPE:
- Some aldehydes (Clidox), phenolics (Sporicidin), and blended activated hydrogen peroxide & acid products (Peridox) require special PPE
- Always consult the product label and SDS prior to using a disinfectant
- If possible, select a less hazardous product
- Most of these products are used to inactivate bacterial spores
Some disinfectants can leave a residue or produce an unpleasant odor:
- Bleach and some quats can leave residue
- Iodophors can stain
- Phenolics can have a strong, unpleasant odor
- Activated hydrogen peroxide can leave a slight residue that easily removed with water or alcohol
- Alcohols leave no residue
Some products may come in a concentrated form where the user has to dilute it before use. Others come in a ready-to-use (RTU) form:
- RTU products can be more expensive upfront, but require no preparation time (cost savings = reduced researcher prep time)
- RTU usually contain stabilizers and tend to last longer than diluted products
- Concentrated products can be more cost-effective upfront but require more researcher preparation time
- Disinfectants diluted from concentrate must be replaced on a more frequent basis and require more monitoring to avoid using expired dilutions
There are seven broad categories of disinfectants. Each has different benefits and limitations:
| Type | Properties | Limitations |
|---|---|---|
| Activated Hydrogen Peroxide (AHP) |
|
|
| Alcohols |
|
|
| Aldehydes |
|
|
| Chlorine (bleach) |
|
|
| Iodophors |
|
|
| Quaternary ammonium compounds (quats) |
|
|
| Phenolics |
|
|
The OSHA Bloodborne Pathogen Standard is designed to protect workers from exposure to Bloodborne Pathogens, including but not limited to HIV, Hepatitis B, and Hepatitis C. It requires that work surfaces that are contaminated with blood or other potentially infectious material (anything from the human body, including human cell lines) or that have the potential to have become contaminated during the course of work be decontaminated with an appropriate disinfectant.
Any lab that works with human material must use an appropriate disinfectant to disinfect work surfaces or to decontaminate surfaces and equipment after a spill. Currently, OSHA recognizes the following as appropriate disinfectants:
- EPA-registered tuberculocidal disinfectants (EPA-registered list B)
- EPA-registered disinfectants that are labelled as effect against both HIV and Hepatitis B (EPA-registered list D)
- Diluted bleach solutions (10% or greater dilution of household bleach which equates to 0.5% or greater sodium hypochlorite)
- Sterilants/High-Level Disinfectants cleared by the FDA (Note: most researchers don’t use these products)
- Please note that 70% ethanol is not recognized as an appropriate surface disinfectant by OSHA. Evaporation of the alcohol prevents sufficient contact time to inactivate Hepatitis B
To check if your product meets the OSHA requirements:
- Locate the EPA registration number found on the product label of your disinfectant
- Go to the appropriate EPA list using the links above
- Search the list using the first two sets of numbers in the EPA registration number
- For example, if your product label lists the EPA registration number as 777-99-675, search the list for 777-99 (omit 675 from your search)
The last number is the distributor identification number. These will not be included on the EPA lists since only the initial formulation submitted to the EPA is listed.
If the EPA registration number appears on one of these lists, the disinfectant is appropriate to disinfect surfaces where human blood or material has been handled.
Learn more about Bloodborne Pathogens
