Criteria for microbiological testing: COSSMA

When launching cosmetic products, manufacturers must make sure that they are safe and stable. This includes a safe microbiological condition. Regular analytical tests are an elementary part of every release process.

According to Article 3 of Regulation (EC) No 1223/2009 (EU Cosmetics Regulations) cosmetic products must be safe for human health¹:

“A cosmetic product made available on the market shall be safe for human health when used under normal or reasonably foreseeable conditions of use …”

This safety also includes the microbiological quality of a cosmetic product.

There is an obligation to inspect products regularly

The microbiological quality must be taken into account when preparing the safety report (Annex 1 Part A of Regulation (EC) No 1223/2009). This applies not only to the cosmetic end product but also to all the raw materials used.

This results in an obligation to inspect products regularly to ensure the qualities correspond to the requirements. Excluded from this are products which, due to their material properties and composition, do not offer any growth opportunities for microorganisms. These products are referred to as microbiologically low-risk products and include:

products with very low or very high pH values (≤ 3.0 or ≥ 10.0)
anhydrous products
products with more than 20% alcohol
solvent-based products

Further examples, a description of the criteria and a decision tree for determining whether a product is to be classified as low-risk or not can be found in DIN EN ISO 29621².

Regular product inspection is mandatory. Photo: Tmc Photos/Shutterstock.com

As part of a suitable microbiological quality management (MQM) system, raw materials and intermediate products are regularly microbiologically tested in addition to the finished products. Controlling operational hygiene through regular sampling (water, air, operating and auxiliary materials, surfaces, etc.) continues to be part of such a system.

The frequency of microbiological tests is determined on a product-specific basis. However, as a rule, at least one product is tested per batch³.

With regard to the maximum allowed content of microorganisms, the requirements of DIN EN ISO 17516 have established themselves as the state of the art⁴, see table 1.

fig. 1: Growth of Pseudomonas aeruginosa on medium

What leads to classifiying a product as unsafe?

Exceeding the legal limits mentioned above, detecting a specified micro-organism or detecting other, possibly pathogenic germs usually leads to classifying a product as unsafe. Follow-up checks at certain time intervals must be performed to answer the question whether or not a germ grows over time.

Once microbes have been identified, research into what caused them must to be done.

It is also recommended that any growth of microorganisms (even if the value is below the values mentioned above) should be accompanied by identifying them. This provides important information on the possible source of input (water, other raw materials, environment, packaging etc.).

Last but not least, the results of microbiological product testing must always be considered and evaluated taking into account product-relevant factors, among which:

product composition
type of use
user group: children, elderly people
type of packaging

Pseudomonas aeruginosa
General information and origin: belongs to the family of Pseudomonads gram negative, movable rods obligate aerobic widespread in soil and water pathogenic for humans and animals

Regular product inspection is mandatory. Photo:Kateryna Kon/Shutterstock.com

Pseudomonas aeruginosa: Relevance for cosmetics

Pseudomonas aeruginosa, see box, is a microorganism which is relevant for the cosmetics industry. This is why it is regulated in DIN EN ISO 17516.

Due to its pathogenic properties (e.g., causing purulent inflammations), according to DIN EN ISO 17516 Pseudomonas aeruginosa must not be detectable in 1g of product.

An important characteristic of Pseudomonas aeruginosa is its extreme undemanding attitude towards external living conditions. Pseudomonas aeruginosa is able to survive for a long time in both humid and dry environments.

In cosmetic manufacturing plants, pseudomonads can occur wherever there are sufficient amounts of water (washrooms, pipes and equipment with residual moisture, water systems, etc.). They can adapt to the environment and thus defy disinfection.

In addition to its resistance and ability to survive in unfavourable environmental conditions, this microorganism is particularly critical because it is frequently found in biofilms. The detachment of individual parts of the biofilm, which are then distributed irregularly into the product, makes it particularly difficult to detect the microorganism reliably and safely during the finished goods release testing.

Even with small amounts of this bacterium in the product, it is important to observe its further development. In many cases, there may be a delay before the germ count increases.

Parameters	Cosmetics for children under the age of three around the eyes mucosal	other cosmetic products
Total number of aerobic mesophilic microorganisms (bacteria, yeasts and moulds)	≤ 100 CFU*/g or mla	≤ 1000 CFU/g or mlb
Specified microorganisms (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans)	Absence in 1g or ml product	Absence in 1g or ml product

Important causes of contamination

lack of cleaning and disinfection of
- the water treatment plant
- the water supply system
- the manufacturing equipment (systems and equipment)
lack of plant design e.g.
- residual water in plants and pipes
- dead spots
- incomplete cleaning, disinfection

The consequence of faulty plant design or errors in cleaning and disinfection is usually that a biofilm forms in the water system or in plant components, especially in pipelines, seals, valves, among others.

In the form of biofilms Pseudomonas aeruginosa is largely protected from:

high temperatures
pH-value fluctuations
chemical disinfectants
ultraviolet radiation

What are the main preventive measures?

It is very important to have a proper plant design and to make sure that the water system is cleaned and disinfected. It is very important to prevent the formation of biofilm, as the removal of an existing biofilm tends to be very difficult.

It is also imperative to ensure a correct cleaning and disinfection of production equipment (systems and equipment)

In addition, good operational and personnel hygiene are crucial.

Literature

¹ Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009, as amended

https://ec.europa.eu/health/sites/health/files/endocrine_disruptors/docs/cosmetic_1223_2009_regulation_en.pdf

² DIN EN ISO 29621, Cosmetic products - Microbiology - Guidelines for risk assessment and identification of low-risk microbiological products, 2017

https://www.iso.org/standard/68310.html

³ https://web.dgk-ev.de/publikationen-fg2/

⁴ DIN EN ISO 17516, Cosmetic products - Microbiology - Microbiological limit values, 2015

www.iso.org/standard/59938.html

Dr Bernhard Fellenberg,
Technical

Consultant,
BAV Institute

Offenburg, Germany

www.bav-institut.de

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