Disinfection and Sterilization: Differences Between The Two Processes.

Disinfection and sterilization are both processes of decontamination. Based on the purpose of decontamination, you can opt for the one you would like to. While disinfection is considered as the process of reducing or eliminating harmful microorganisms from inanimate objects, as well as surfaces, sterilization is the one of killing all microorganisms.

So, this is the main difference that exists between sterilizing and disinfecting. Sterilization can also destroy the spores of different organisms that are present on surfaces, in medications or liquids, or compounds like biological culture media. Such, let’s say, extreme forms of decontamination are always needed during critical times such as surgery or in environments such as industrial, laboratory, as well as a hospital. It is more practical to use disinfection in everyday life.

• The methods of disinfection and sterilization.

Disinfection is often carried out by utilizing disinfectants or better said chemicals. Some of those disinfectants may be quite effective, and they have a wide spectrum, as they are able to destroy a wide range of microorganisms. At the same time, there are also others that may have a narrow spectrum, but they may be easy to use, be non-toxic, or also inexpensive.

On the other hand, sterilization may be done by three methods: physical, chemical, or physicochemical. The physical method includes radiation, heat, and filtration. In contrast, the chemical one includes the use of liquid and gaseous chemicals, and the physiochemical is the combination of the physical and the chemical method.

The physical methods of performing sterilization are very important in the veterinary and the health care industry, where it is important to destroy highly resistant pathogens. Medicinal equipment should be thoroughly sterilized, as it is utilized in invasive procedures with humans and animals. Bacteria, or also viruses and fungi, will not have the ability to stand up sterilization.

When it comes to disinfection, it includes the following methods and types:

• Air disinfectants;
• Alcohols;
• Aldehydes;
• Oxidizing agents;
• Phenolics;
• Quaternary ammonium compounds;
• Common sodium bicarbonate and so on.

The ideal disinfectants which are utilized in disinfection should:

• Have the ability to kill microorganisms within a stipulated period;
• Have a broader spectrum of performance;
• Have to possess a longer shelf-life;
• Have the ability to perform any pH;
• Not be toxic, as well as allergic;
• To be active in the presence of organic matter.

When it comes to sterilization, it includes the following methods:

• Irradiation (Gamma or E-Beam);
• Wet heat (Autoclaving);
• Ethylene Oxide gas;
• Filtration;
• Flaming;
• Tyndallization;
• Incineration;
• Steam Sterilization;
• Radiation (UV, x-rays and gamma rays exposure);
• Dry Heat Sterilization (Flaming and Baking).

Here are some of the most frequently used methods and types of disinfection and sterilization.

• Differences between disinfection and sterilization.

There are several differences between disinfection and sterilization, and some of them are the following:

Disinfection: Disinfectants are antibacterial agents that kill pathogenic microorganisms, without including spores, which survive on inanimate objects.

Sterilization:  It is the process that kills all viable microorganisms, bacteria, spores, and viruses. It is also an absolute germ-free state.

• Application to medical equipment.

Disinfection: Oximeters, ECG machines, bed-pans, gastroscopes, and urinals.

Sterilization: Biopsy and surgical instruments, cystoscopes, foot care instruments, scalpels, artificial pacemakers, scissors, syringes, and hypodermic needles.

• Status of cleanliness.

Disinfection: Adequate cleanliness.

Sterilization: Absolute or extreme cleanliness.

• Different types of sterilization agents and disinfectants.

Disinfection: Sodium Hypochlorite, Glutaraldehyde, Iodophor compounds, phenolic compounds, Amphoterics, Quarternary Ammonium Compounds (QAC’s or quats), Clorox, Lysol, Peracetic acid, Chlorine dioxide, Aldehydes, Hydrogen peroxide, Ozone gas, performic acid, Potassium Peroxymonosulfate, Potassium permanganate (KMnO4), Lugol’s iodine solution, Thymol-based disinfectant, Copper Alloys, Silver, Propylene glycol and triethylene glycol, benzalkonium chloride.

Sterilization: Ethylene oxide gas, Plasma gas, Chlorine dioxide, Nitrogen Dioxide, Ozone, Hydrogen Peroxide, Glutaraldehyde and formaldehyde, Peracetic acid, Radiation sterilization (electron beams, X-rays, gamma rays, or irradiation by subatomic particles), Moist heat in autoclaves, Dry-heat in ovens.

• Processing time.

Disinfection: In disinfection, the processing time depends on the process that is adopted: For instance, heat-sensitive semi-critical medical patient care objects may be purified for fifty minutes.

Sterilization: In sterilization, the processing time depends on the process: For instance, heat-tolerant critical equipment can be sterilized by the use of steam and dry heat. This also depends on the temperatures.

• New methods of applying disinfection and sterilization.

Disinfection: Cidex OPA (Ortho-phthalaldehyde) – FDA Cleared, Sterilox (Superoxidized water) – Not FDA/EPA cleared, Surfacine (Antimicrobial coating) – Not FDA/EPA cleared.

Sterilization: Endoclens (Liquid sterilization process) – Not FDA cleared, Rapid readout ethylene oxide biological indicator (Attest) – Not FDA cleared, New Plasms Sterilizer (Sterrad 50) – FDA cleared.

So, from all that we mentioned above, we can conclude that these two techniques, although they seem quite similar, they are, in fact, quite different, not only because of the methods they use but also because of their use in different fields of life. Disinfection minimizes the number of microorganisms but does not eliminate them, while sterilization is the technique that eliminates all microorganisms.