Cleaning, Disinfection and Sterilization
These three terms have similar features but each has distinct and important differences
Cleaning is usually restricted in meaning to the physical removal of surface contaminants, usually with detergents or soap and water, ultrasound or other methods. While cleaning does remove soils and bacteria, cleaning does not include any component of virus or bacteria killing or inactivation though it does have the effect of dis-infection by mechanical means (physical removal). Even the most thorough cleaning leaves microorganisms on the surface of the item. The use of an ultrasonic cleaner with detergents is able to dislodge fine particles from surfaces that may be inaccessible by physical scrubbing or brushing. It is more diffiult but not impossible to sterilize a surface that has not been properly cleaned first.
Disinfection is the killing or inactivation of some of the microorganisms on the surface of an object without the claim for killing or inactivating all microorganisms. For tools and small objects this generally refers to the effect of immersion in a liquid “germicidal”.
For items that can’t be immersed in a liquid germicidal, the area or object must first be washed and then the surface coated, usually by spraying, and then allowed to air dry.
A liquid germicidal’s effectiveness is dependent on contact of the germicidal liquid to the virus or bacteria to be killed but other factors such as pH, temperature and microbial load (concentration) also play a part which can defeat an intended level of disinfection.
Effective cleaning is the most important step because bacteria and viruses may survive beneath a layer of dirt, beneath grease, dried blood, or in crevices or places that are difficult to reach by cleaning that shield the organism from direct contact with the disinfectant. Disinfecting solutions require the object be effectively precleaned before liquid disinfection.
Liquid disinfectants require specific solution strengths and contact time so it is mandatory to be familiar with the product by reading and following the label instructions and warnings.
All disinfectants do not destroy all types of microorganisms and some may leave harmful chemical residues which must be removed prior to sterilization or use. They are almost all harmful to humans and animals.
While disinfectants used as soaking agents seem to add a margin of safety to the cleaning process, the use of disinfectants themselves present other dangers.
Application of alcohol, clorox or boiling is considered disinfection not sterilization. Most HDs require biological testing to verify the process. These methods cannot be routinely tested for effectiveness.
Disinfectants (meaning hard surface disinfectants) within the tattoo and piercing environment are most appropriately used on potentially contaminated objects which do not require sterilization, such as certain tools, counters, lights, chairs, etc.. Disinfection by physical means, such as in an autoclave, is also effective when used at less than sterilizing requirements. In the US, disinfectants designed for use on the skin are usually called antiseptics to distinguish them as a separate group with different specifications.
STERILIZATION means rendering an object free of all living microorganisms including bacterial spores, one of the hardest to inactivate.
Though this is phrased as an absolute it is actually only a probability on a curve and an item is generally considered sterile if only one microbe may survive on a million sterilized products.
Sterilization is most frequently done by raising the temperature of an object to a level sufficiently high to kill all microorganisms. Since the entire object is raised, the problem of microorganisms being shielded by a layer of material is reduced but increases the challenge of the process to overcome the actual microbial load or burden. Autoclave sterilization by heat, steam, pressure and time is nearly universally accepted. Application of alcohol or bleach or boiling is disinfection not sterilization though under certain circumstances they too can sterilize.
Sterilizing solutions require the object be effectively precleaned. The microbial load must be reduced by cleaning so that the process will be able to statistically achieve that one in a million probability.