Bilgiye hızlı erişim:
The expiration date on cosmetic product labels refers to the shelf life of the product when stored in its unopened packaging. However, once the product packaging is opened, the contents are directly exposed to external factors such as air, humidity, microbial contamination, and contact from consumers. Therefore, the microbiological and physical stability of cosmetic products after opening must also be evaluated.
This evaluation is conducted through the PAO (Period After Opening) Test. The PAO test is an important analytical method in product safety, assessing the microbiological safety and formulation stability of a product during its post-opening period.
What is the PAO Test?
The PAO test is performed to scientifically identify potential deterioration risks that a product may encounter during use after opening. The aim of this test is to evaluate the microbiological, physical, and chemical stability of the product over its usage period once opened. The goal is to determine with objective, scientific data whether the product remains safe and effective throughout the specified period.
Within the scope of the test:
The product is stored and monitored under controlled conditions for a specified period.
Microbiological load checks are conducted at designated intervals.
Visible physical changes (color, odor, consistency, separation, etc.) are recorded.
The pH value and density of the product are monitored to assess the chemical stability of the formulation.
The product is evaluated in terms of both microbiological safety and formulation stability.
The results obtained provide the basis for determining the period during which the product can be safely used by consumers after opening.
What Does the PAO Symbol Mean?
The open jar symbol found on cosmetic packaging and the number next to it indicate the PAO period. This shows how many months the product remains safe and effective for use after opening.
Example PAO symbols:
6M → The product remains stable for 6 months after opening.
12M → The product remains stable for 12 months after opening.
24M → The product remains stable for 2 years after opening.
This symbol is particularly important in informing users of the product's performance period after opening, especially for products with a long shelf life.
Why Should the PAO Period Be Tested?
The accuracy of the PAO period is important not only for regulatory compliance but also for consumer health and brand reliability. PAO testing is recommended for the following reasons:
To provide scientifically based data regarding consumer safety and product liability
To identify potential deterioration risks in advance
To ensure accurate and legally compliant placement of symbols on packaging design
To fulfill obligations under the Cosmetic Products Regulation (EC 1223/2009)
PAO Test Process at Cosming
At Cosming, PAO tests are conducted by carefully monitoring microbiological load changes, and chemical and physical parameters of the product throughout its usage period. The testing process includes the following steps:
The product is stored under conditions appropriate to the testing period and storage requirements in a controlled environment.
Microbiological analyses are performed at regular intervals.
Observed chemical, physical, and sensory changes (color, odor, consistency, etc.) are recorded.
At the end of the test period, the product's usage safety is evaluated and reported.
The data obtained at the end of the test process are presented to the manufacturer to support the accuracy of the PAO period stated on the product packaging.
You can contact us to analyze the stability and safe usage period of your products after opening.
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