Consumers expect a high degree of cleanliness from water and beverage delivery systems. Unfortunately, these devices present a real hygiene challenge.

Tubing, filters, reservoirs, and dispensing systems provide warm, wet environments with plenty of nutrients — ideal conditions for microbes.

Cleaning these systems is essential, but has potential pitfalls, including its dependence on worker consistency, potential residuals from cleaning solutions and the challenge of obtaining hard-to-find parts. Some cleaning alternatives require expensive equipment or costly maintenance.

Aesthetics are important

<align=”justify” />Microbe growth does not always have health implications, but it can degrade the appearance of the system, hurt functionality, or harm product taste.

In addition, biofilms that form when bacteria colonize can slough off and colonize other surfaces or end up as unsightly particles in a drinking glass. Biofilm growth inside filters can reduce flows and turn the filter itself into a source of bacteria.

Silver zeolite technology weds the well-known benefits of silver with new “smart-material” technology, resulting in a new tool that can be used by POU/POE manufacturers and dealers fighting for good hygiene and product quality.

New technologies

<align=”justify” />Silver-based antimicrobial additives can prevent the growth of microbes in liquid handling systems.

These additives, certified by the Environmental Protection Agency (EPA), Food and Drug Administration (FDA), and NSF International, can be incorporated into the water contact parts during manufacture and are safe for food and water contact.

Silver zeolite technology is at the center of this advancement in antimicrobial protection.

Silver has been used for generations for its antimicrobial effectiveness. A naturally occurring element, silver is safe enough to be used in hospitals nurseries, burn wards and in catheter applications. At very low levels, silver prevents the growth of a wide range of bacteria, mold and fungi.

The breakthrough in this latest technology was achieved through the loading of silver atoms into a zeolite particle. This silver zeolite chemistry controls when and how much silver is released.

A “smart material” responds to the environment by releasing silver only when the conditions are right for bacterial growth.

In other words, it conserves the active ingredient when not required, yielding longer-lasting antimicrobial protection.

Results in the field

<align=”justify” />Laboratory and field tests show very positive results. For example, when common water bacteria samples are placed on a silver zeolite-treated water cooler part, the bacteria count is reduced by 99.999 percent versus an untreated part.

Field test data is equally encouraging: Biofilm build-up was essentially prevented for over a year in a commercially available cooler. These same coolers showed a corresponding drop in effluent bacteria counts.

Safety requirements

<align=”justify” />In addition to excellent controlled release characteristics, zeolites meet the safety requirements for use in drinking water systems.

The US government requires that the antimicrobial agent be registered with the EPA and approved by the FDA for use in materials that are in contact with food and water.

Silver zeolites have undergone extensive safety testing and have been registered and approved for food and drinking water contact.

If you are considering a particular product, confirm that drinking water applications are specifically listed on the EPA label.

Built-in protection

<align=”justify” />Building silver zeolite protection into a particular product is straightforward. The antimicrobial comes as a fine, flowing powder that is easy to mix.

It can be processed at high temperatures — up to 800 degrees Celsius. The zeolite will not degrade or decompose during processing.

Adding silver zeolites to plastics is similar to adding a colorant. A polymer concentrate is made at 20-30 percent using an extruder. This concentrate is then mixed or “let down,” with the final resin before the part is formed.

Therefore, zeolite is distributed evenly throughout the polymer, typically 1 percent to 5 percent by weight to the final product.

Each application requires careful review with the supplier’s engineering staff to determine the appropriate addition rate, how much silver should be loaded on the zeolite, and lastly, which size particle will work the best.


Brian McBride is the business development manager with antimicrobial products manufacturer AgION Technologies, Inc., Wakefield, MA.