ROANOKE, Va. — I recently received this question from a military reader:

“Do you have any guidelines/specifications for processing and sterilizing reusable surgeon gowns?”

The job of a laundry is to take a soiled/contaminated reusable item and return it to a hygienically clean state. The laundry process is not designed to sterilize the item being washed but rather to significantly reduce the contamination level to an acceptable safe level.

A wonderful study was conducted many years ago by the Department of Veterans Affairs, and it determined that the No. 1 factor in reducing the level of bacteria or virus on a piece of soiled textile product is the simple act of dilution.

Every time you fill a washer with water, agitate it for at least a minute and then drain, you remove more than 90% of all the bacteria or viruses on the textile product. Most conventional washers will have a minimum of seven fills and drains.

In processing reusable barrier gowns, I have always sorted them together, separate from any item containing cotton. This allows for a unique wash formula designed just for this type of product and also prohibits lint from showing up on the end product. 

Because of their lightweight nature, I found it necessary to under-load a washer-extractor by 25% of rated capacity. Mechanical action is always an important factor in obtaining clean textile products, and under-loading is required to ensure proper mechanical action in the wash load.

The next question is how I prevent stains and remove soils that are inherently found in the surgical suite, like blood, fat, oil and medicine. Blood is the easiest item to remove from the textile product as long as you follow this guideline: The initial rinse must be under 120 F. Anything over that temperature will cause the blood to set and make a stain.

Blood becomes more soluble the closer it gets to 120 degrees. My mother always told me to use cold water to rinse out a spot of blood on a shirt, but warm water works better and faster. As a precaution to avoid any residual blood from setting in future wash steps, I recommend adding a little alkali to the first rinse. Blood will not set in the presence of alkali.

The hardest stain to remove from a microfilament high-thread-count gown or a tri-layer laminate is oil. These fabrics love oil. My recommendation to handle this problem is to use a solvated detergent in the first rinse and to run that rinse for at least five minutes. Once the temperature goes above 120 degrees, the solvent will become ineffective.

Traditional laundry procedures would call for large amounts of alkali to be used to remove the oil. Barrier fabrics will be damaged by high concentrations of alkali; therefore, they should be avoided.

I recommend washing barrier fabric in conventional washers only. The use of a hydraulic extractor on the end of a tunnel is not good for the fabric, and this type of fabric does not make a good cake, which will not transfer well from on the press to the dryers.

The most important reason is that proper wash formulations for this type of product is difficult to maintain in a tunnel, based on the natural water reuse system built into the equipment.

It is key for the processor of reusable barrier fabric to realize that the fabric does not absorb any chemicals and that every surfactant that you use in the wash process must be completely removed to ensure proper barrier performance.

In washing these textile products, using less is very desirable. Therefore, the wash formula needs to contain a number of rinses and at least one intermediate extract. Proper rinsing is the key to good barrier performance.

I’ll finish this next issue with more thoughts on chemistry, extraction, drying and inspection.