Over the years, I’ve been asked many times to explain how laundering decontaminates fabrics or textiles.
The questions have been asked in several ways; usually asking about sanitization or disinfection of the textiles, especially if considering textiles that are used in healthcare facilities or even in hotel and motel operations.
I’m willing to venture that many of you have been asked the same question: “How clean is clean?”
First, we need to know that in the United States, the Environmental Protection Agency has regulatory authority concerning products that claim to have antimicrobial activity.
This is an area that is highly regulated and standardized, so that everyone that uses these products is aware of the performance claims and the limitations.
The terms sanitization, disinfection and sterile all have precise meanings according to microbiologists and the EPA.
To sanitize a product, one must decrease bacterial levels by 99.999%, which is also known as a “5-log reduction” in pathogens.
Disinfection is not an “official” term, but is also sometimes considered the same as sanitization.
Sterilization means complete destruction of all pathogens.
HYGIENICALLY CLEAN TEXTILES
In laundry operations, we usually describe the reduction of pathogens in the textiles as achieving hygienically clean textiles.
One reasonable definition of hygienically clean is that the textile has been treated such that bioburden has been adequately removed so that the item can be used without fear of being a source of contamination in a healthcare use.
The Association for the Advancement of Medical Instrumentation (AAMI) defines the term hygienically clean as “free of pathogens in sufficient numbers to cause human illness.”
The laundering process includes several techniques to assure that bioburden or pathogens are reduced or eliminated. These techniques include:
Several water changes during the cleaning process physically remove and flush away bioorganisms. Mechanical action is also a factor to consider as bioburden is loosened from the fabric by proper mechanical action.
Washing at elevated temperatures (>140 F) deactivates much of the common bioorganisms.
Changes in pH
A high pH (>10.5) will “attack” or deactivate bioorganisms. In addition, large swings in pH, from neutral (7.0-8.0) in first flushes to alkaline (10.5-11.5) during the main wash cycles to acid (5.5-6.5) will adversely affect bioorganisms.
This is where the bleaches contribute to the bioorganism deactivation.
Chlorine bleaches are well known to have excellent antibacterial and antiviral efficacy. Oxygen bleach is considered to be somewhat less aggressive on bacteria and viruses, but when combined with the other cleaning factors in a laundry formula, it’s considered effective in deactivating residual microbes.
Drying at temperatures that exceed 180 F on the fabric surface deactivates any potential remaining organisms.
Chemical Sanitizers or Bacteriostats
This is where the EPA can get involved. Some laundries, as an extra precaution, will use EPA-registered products that will act as sanitizers in the final step of the laundry process. Many laundry chemical suppliers have products that they have registered with the EPA that can claim to sanitize the fabric in the final rinse.
In addition, some of these products will leave active materials in the fabric that will inhibit the potential growth of bacteria if the fabric has been contaminated. These products are called bacteriostats.
Published reports by NAILM (the National Association of Institutional Linen Management), TRSA (the Textile Rental Services Association of America), CDC (the Centers for Disease Control and Prevention) and AAMI indicate that a well-designed wash formula that appropriately uses the above techniques will provide “hygienically clean” textiles.
Further, the Veterans Administration sponsored a research study that investigated the effect of low temperature and chemical oxidation on the “hygienically clean” aspects of the laundering process used in its laundry facilities.
The study is titled Killing of fabric-associated bacteria in hospital laundry by low temperature washing (Blaser, et al., Journal of Infectious Diseases, Vol. 149, No. 1, Jan. 1984, 48-57).
The article concluded that there was sufficient reduction of pathogenic bacteria, even in low-temperature washing (22 C; 72 F).
It also noted that even with the elimination of chlorine bleach, adequate reduction in pathogens was observed in low-temperature washing when compared to traditional high-temperature (71 C; 160 F) washing processes.
Another aspect of washing textiles that has become more of a concern for some is whether they can be rendered hypoallergenic in the laundry.
Hypoallergenic is a term that’s somewhat loosely defined, but is usually understood to mean that the product in question has fewer tendencies to cause allergic reactions to the user.
Hypo means “less”, not “none.”
It’s generally understood with products such as cosmetics that specific additives that may cause skin sensitivity (synthetic preservatives, toxins, fragrances or other chemicals, for example) have been removed from the product.
In addition, many allergens are natural, such as pollens, pet dander, molds, dust mites and residues from mice or cockroaches. So, hypoallergenic may also be taken to mean that these allergens are at a minimum.
In producing hypoallergenic textiles, the objective is twofold.
First, the laundry must remove any potential environmental contaminants from the fabric that may have been deposited on the textile.
Second, the laundry must treat the fabric with detergents and cleaning materials that have a low potential for causing a sensitivity reaction by users of the textiles.
The first objective – to remove allergens – is very similar to the objective to remove pathogens, such as when we achieve hygienically clean textiles.
Thus the same aspects of the laundering process have an impact:
• Dilution and mechanical action loosen and flush away allergens.
• The heat of the water will deactivate many allergens.
• Oxidizers and detergents can deactivate allergens.
• The heat of the dryer can also help deactivate allergens.
The second step that must be considered is to eliminate potential allergens from being introduced to the fabric.
It’s suggested that you should not use softeners, and especially softeners with a high degree of fragrances. Extra rinsing with softened water is also recommended. And if deionized water is available, you may want to consider using that in the final rinse.
Treated this way, although you cannot claim that the fabric is allergen-free, you can claim that the fabric is hypoallergenic.
So, the next time you’re asked how clean your textiles are, you can give them an answer that’s backed by science!