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What Are The Differences Between Disinfection And Sterilization?

Ethylene oxide sterilizer

Disinfection and sterilization are two processes commonly used to kill microorganisms that may cause disease. While both processes involve killing microorganisms, they differ in the degree of killing, methods used, site of application, and other factors.


Disinfection is an act of disinfecting using specialized cleansing techniques that destroy or prevent the growth of organisms capable of causing infection. Mainly, chemicals are used to kill germs on surfaces. This process does not necessarily clean dirty surfaces or remove germs. Still, by killing germs after cleaning, it can further lower the risk of spreading infection.

Cleaning table with disinfectant spray bottle washing surfaces with towel and gloves

Sterilization is the process of destroying all microorganisms and their pathogenic products. Sterilization kills or eliminates all forms of microbial life and is carried out in medical facilities by physical or chemical methods. All medical devices, such as disposable infusion sets and syringes, are sterilized before they are sold to the market. Our factory will sterilize the products after due inspection. Sterilization protects the infusion sets from microorganisms that can cause infections to would-be users. 


Means of doing disinfection

  • Chemical disinfectants
  • Miscellaneous inactivating agents

Means of doing sterilization

Ethylene oxide “gas” sterilization (ETO)

This sterilization method involves using colorless gas that is both flammable and explosive. Our products, infusion sets, are usually sterilized by ETO. Before utilizing the product, end-users are advised to verify the presence of the Ethylene Oxide (EO) symbol on the packaging.For this method to be effective, there are four parameters to be observed:

  1. The gas concentration should be from 450 to 1200 mg/l.
  2. The temperature of 37 to 63℃.
  3. Relative humidity of 40 to 80%.
  4. The exposure time of 1 to 6 hours.

To shorten the sterilization time, the gas concentration should be increased, and the temperature should be decreased.

The basic cycle for ETO sterilization consists of five stages: (1) preconditioning and humidification, (2) gas introduction, (3) exposure, (4) evacuation, and (5) air washes. The whole cycle takes around 2 ½ hours, excluding the aeration time.


  • Steam sterilization
  • Flash sterilization
  • Low-temperature sterilization technologies
  • Hydrogen peroxide gas plasma sterilization
  • Peracetic acid sterilization
  • Infrared radiation
  • Advanced filtration
  • Pressurized steam (autoclaving)
  • Dry heat cabinets (for medical instruments)
  • Ionizing radiation (typically used for medical equipment)

Criteria of effectiveness


Based on Environmental Protection Agency (EPA) standards, a disinfectant must kill 99.999 percent of germs. 


If a device has been sterilized, it does not mean that no viable microorganisms have survived the process. There could be some which survived it, depending on the level of sterilization. The number of viable microorganisms that survive a particular sterilization method is known as the sterility assurance level (SAL). If the SAL is at the level of 0-5, then one viable microorganism out of 100,000 survives the sterilization. A SAL level of 0-6 is required for medical devices, which means that only one viable microorganism out of 1,000,000 survives the sterilization method.

Safety Tips

For disinfecting

  • Always ensure that your product is a disinfectant. Look at the label because most of the time, the manufacturer will indicate if it is a disinfectant. 
  • Try to find out if the product is designed to kill. If so, find out what bacteria, fungi, or viruses are killed by the disinfectant. This information is crucial if you are looking for a disinfectant to kill COVID-19 viruses.
  • Ensure that the product you bought kills germs. Sprays and wipes may be helpful for cleaning, but they cannot kill germs. Would you please not buy them? 
  • Do not combine chemicals, such as hydrogen peroxide and bleach.
  • Wear gloves. Handling disinfectants could irritate the skin; hence, avoid having contact with them.
  • Let the disinfectant stay on the surface being treated for the right amount of time. Follow the manufacturer’s instructions written on the label regarding how long it should stay on the surface. If not mentioned explicitly in the instructions, do not wipe or wash the disinfectant away. 
  • Use the disinfectant in a well-ventilated area. This is especially important if the product contains bleach.
  • Safely store your disinfectants. Ensure to return the cap of the container after use and close it tightly. Keep them away from the reach of children. Store them in a cool and dry place, and discard them if they have expired. 

For sterilizing

Ethylene oxide “gas” sterilization

  • ETO has several toxic effects. Exposure to ETO can cause eye pain, sore throat, difficulty in breathing, and blurred vision. If exposed to ETO, the affected individual will experience dizziness, nausea, headache, convulsions, blisters, vomiting, and coughing. Based on animal studies, exposure to ETO could also cause cancer. For all of these reasons, avoid exposing yourselves to ETO as much as possible.


Pressurized steam (autoclaving)
Pressurized steam (autoclaving)
  • Load the autoclave adequately based on the manufacturer’s recommendations.
  • Before placing any material to be sterilized in the autoclave, be sure to clean the drain filter. 
  • Before placing the containers of liquids inside the autoclave, you should loosen the caps to prevent the shattering of the bottles during pressurization.
  • Use a tray having a solid bottom and walls to enclose the bottles and catch spills.
  • Add ¼ to ½ inch of water so that the bottles will be heated uniformly. 
  • Refrain from loading plastic materials that are not compatible with the autoclave.
  • Individual glassware pieces should be placed in a heat-resistant plastic tray on a shelf or rack and never placed directly on the autoclave bottom or floor.
  • Make sure that the autoclave door is fully closed and that the correct cycle has been selected before starting.
  • Use heat-resistant gloves when opening the autoclave door after a run.
  • Do not immediately remove items from the autoclave. Wait five minutes for loads containing only dry glassware and ten minutes for autoclaved liquid loads.
  • When withdrawing items from the autoclave, wear protectors such as a rubber apron, rubber sleeve, heat-resistant mitts, and a face shield. Remove the load and let the glassware cool for fifteen minutes before touching it with unprotected hands.
  • Pay much attention to autoclaved liquid bottles which are still bubbling. Let the liquid loads stand in a safe and least likely disturbing place for a full hour before touching them with unprotected hands. Bear in mind that hot glassware and liquids could cause burns and severe harm. 

Summary of the difference between disinfection and sterilization

Points of differencesDisinfectionSterilization
Main actionKill some germs after cleaning the surfacesKill and eliminate all forms of microbial lives
Degree of killing pathogenic microorganismsA certain percentage of microorganisms are killed, less than 100%.One hundred percent (100%) of microorganisms are killed.
MethodsMainly chemicalsChemicals and other methods as enumerated in the preceding
Criteria of effectiveness According to  EPA standards, a disinfectant must kill 99.999 percent of germs.Sterility assurance level of 10-6.Probability of one spore surviving in a million.
Site of applicationsAt homeMedical clinics, hospitals, medical factories
ExamplesSpray, wipe, and other liquid formsAcidic materials, autoclaving equipment, use of radiation, gases
Safety TipsAs enumerated in the precedingAs enumerated in the preceding
Table 1. Summary of the difference between disinfection and sterilization

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