The safety of hotel guests is the highest priority

For several years now, cosmetic pump dispensers have been suspected of being contaminated with unhealthy bacteria. Therefore, ADA Cosmetics engaged the renowned Rhine-Waal University of Applied Sciences to carry out a scientific hygiene study.

The Context

Various studies since 2011 have shown that one quarter of all refillable cosmetic pump dispensers are contaminated with unhealthy bacteria.

ADA Cosmetics commissioned an independent study from the Rhine-Waal University of Applied Sciences to investigate the extent and source of this contamination in cosmetic dispensers.

The Hypothesis

Previous studies suggested that the contamination found was caused by the refilling process. However, they did not provide any scientific proof of this.

Scope of the study

​A total of 57 standard liquid soap pump dispensers (refillable) and 47 alternative press dispensers (non-refillable) were collected from hotel rooms across Germany. ​

The dispensers were collected when the liquid soap level was between 75% and 25%.​

The Results

A high level of contamination with harmful germs was found in 67% of the refillable pump dispensers (38 out of 57). No contamination of the product (shampoo, liquid soap, shower gel) was detected in any of the press dispensers.

Scientific root cause analysis​

All closed and refillable dispenser systems were actively contaminated with a biofilm solution to replicate the route of contamination during the refill process.​

Finding #1 ​

Refilling was NOT the cause of bacterial contamination in the pump dispensers.* ​

Even if bacteria are actively injected into the liquid, replicating a potential contamination during a refilling process, the shampoo or hand soap’s preservative system** ensured that they do not grow or spread within the liquid. ​


*Under the condition that a minimum level of hygiene is ensured during the refilling process.​
** Under the condition that the formulation contains a proven preservative system (such as that provided by ADA Cosmetics).


All closed and refillable dispenser systems were actively contaminated with a biofilm solution to replicate the standard use in wet conditions in the shower and at the sink.

Finding #2

Contamination of the product occurs through the pump and/or the pump mechanism. The root cause is the pump head, where water collects and a bacterial biofilm builds over time. In most pumps currently on the market, this bacteria is then continuously injected into the dispenser with every use of the pump. ​

The watery biofilm builds up on the surface of the shampoo or liquid soap and continues to grow as the pump is used.

This stagnant surface layer is the perfect base for further bacterial growth. The preservative system is cut off by this layer and thus cannot prevent further growth.

This illustration shows the route of the bacterial contamination.

Over time, the biofilm sinks down into the product or is swirled into the product during the refilling process. At this point, the preservative system is no longer effective.

The process is caused by the structure of the pump systems currently on the market. Instead of pumping air into the dispenser as intended, which would prevent a vacuum from forming as the liquid is dispensed, the pump transports the watery biofilm from the pump head into the interior of the dispenser.

All pump systems that do not have a technical separation between the air and liquid exchange thus create continuous bacterial contamination of the dispenser contents.

The study’s findings show that bacterial growth within the pump dispenser increases significantly after 20 days, significantly increasing the health risks at the same time.

The researchers from the Rhine-Waal University of Applied Sciences in Germany demonstrated this effect for numerous pump dispensers used in hotels as well as those available from drugstores and supermarkets.

All of the contaminated dispenser systems lacked a technical separation between the air intake and the liquid output within the pump head.

Finding #3

As a result of the increasing bacterial contamination of the content, the user’s hands, hair or body come into contact with disease-causing bacteria. This means the level of contamination is greater after washing than before washing.

The researchers from the Rhine-Waal University of Applied Sciences found various bacteria as well as yeast and mold fungus in the investigated pump dispensers, primarily gram-negative types of bacteria (Pluralibacter gergoviae and Pseudomonas aeruginosa).

These kinds of bacteria, some of which are resistant to common antibiotics, can cause severe infections in immunocompromised people. In healthy people, they can cause nausea, vomiting, or eye inflammation.

Push-down dispenser systems with membranes that release the product downward did not show any contamination in the product itself, only a standard level of contamination on the outside of the dispenser from everyday use.

Typical illnesses caused by the bacteria in healthy people include eye inflammation, upset stomach, and nausea.

In the past, people who were affected generally did not know the reason for this or the cause of their symptoms.

Because pump dispensers were only very vaguely suspected as the cause, and only by specialists, other reasons were assumed, such as food poisoning or a transmitted infection.

Finding #4

Dispenser systems without a pump that dispense the contents by mechanical downward pressure are generally protected against any back contamination. ​

Combined with membrane release systems like ADA’s patented SmartCare system, these provide the highest known level of protection against contamination, according to the current state of scientific knowledge.

The scientific study by the Rhine-Waal University of Applied Sciences confirmed that the SmartCare dispenser is one of the most hygienic systems in the world.

  • Liquid can run down the back wall, and no standing water is created. The mechanical pressure on the dispenser from the sides ensures that dirty hands and fingers do not come near the opening.
  • Downward product release physically guarantees that dirt cannot enter the dispenser.
  • In addition, the patented membrane technology prevents back contamination and guarantees the safe exchange of liquid and air backflow.

Find out more about the SmartCare system, its patented membrane technology, and its environmental benefits here: SmartCare.

Finding #5

Pump dispensers with a drainage system are safe. ​

Pump systems like ADA’s SHAPE dispenser with its patented integrated drainage systems prevent any biofilm development due to standing water and separate the air-liquid flow to ensure maximum hygiene.​

The technical separation of the air-liquid flow during the pump activation exchange ensures maximum hygiene and safety, and prevents contamination of the contents.

Find out more about the SHAPE dispenser system here: SHAPE.

The new pump dispenser from ADA Cosmetics, with its patented hygiene pump, provides maximum safety.

The newly developed pump, with a patented drainage system, not only guarantees maximum hygienic safety, but is also the first model to be completely recyclable.

The entire pump, including the interior technical parts, is made from the same material (polypropylene).



Hygiene pump prevents back contamination:

  • Intelligently designed drainage system​
  • Showerproof – no contact with water​
  • 100% product safety guarantee



Do you have more questions? We are happy to help!

Our goal is to offer you and your guests the best possible solution for your hotel bathrooms.

SmartCare is the world’s most hygienic dispenser system. The patented membrane technology, inside a press-down dispenser, offers the greatest ease of use for both for guests and the housekeeping team.

SHAPE’s patented hygiene pump offers the safety of an innovative pump system and the elegance of an advanced concept.

In order to support customers who prefer conventional pump dispensers, we have also developed an innovative hygiene pump that is not only hygienic, but also sets new sustainability standards with its material composition.

Contact our Customer Service team. We are happy to help!

The full hygiene study is available here.

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