Cosmetics Testing - Schülke-Koko preservative efficacy (Challenge) test.
Several types of tests to evaluate the effectiveness of preservatives incorporated into a cosmetic and European legislation does not specify which test should be used (Regulation EC No. 1223/2009 of the European Parliament and the Council of Europe of 30 November 2009 on cosmetics products). The most widely used tests in our environment are made according to the ISO 11930 standard, or according to the European Pharmacopoeia.
Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans: three microorganisms are used in all preservative efficacy tests. In addition, other microorganisms that can cause alteration of the cosmetic (see below) are included. Unlike the method of the European Pharmacopoeia using only pathogenic microorganisms, the Schülke-Koko test includes saprophytes, chosen according to Schülke service experience as cosmetics manufacturer.
In this test an inoculum with a mixture of microorganisms and a volume, relative to the inoculated, lower than that used in the test performed according to European Pharmacopoeia product is used (0.4% vs. 1%), and 6 weekly reinoculations are performed along conducting the test.
The microorganisms used are: Enterobacter gergoviae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas putida, Burkholderia cepacia, Kocuria rhizophila, Staphylococcus aureus, Candida albicans, Aspergillus niger (= Aspergillus brasiliensis), Penicillium funiculosum (= Penicillium pinophilum ).
This test is designed to simulate a more comparable to the conditions in which a cosmetic is used. Thus, by inoculating a mixture of microorganisms, it is possible to obtain a similar situation as could occur in natural conditions of symbiotic growth.