Cossma1607-08_GB

of which had previously passed challenge testing. In one case, we received a natural shampoo for- mulation with an unidentified contamination of unknown de- scent. The alternative preser­ vation system originally imple- mented in the formulation was Dermosoft 1388, a patented mul- tifunctional blend of sodium le- vulinate and sodium anisate. This formulation had passed the origi- nal challenge test with A-criteria. The germ responsible for the con- tamination via PCR (Polymerase Chain Reaction) turned out to be a Lactobacillus, more precisely L. plantarum. Lactobacillus is a genus of non-pathogenic bacteria, which pose a high contamina- tion risk to final cosmetic prod- ucts because of their ubiquitous distribution, e.g. in many fer- mented food products, on fer- mented and intact plant surfaces and in human saliva and the gas- trointestinal tract. We then repeated the original challenge test and compared the Lactobacillus isolated from the contaminated product with a commercial strain of L. plantar- um and the contaminated prod- uct itself. As a result, the Lactoba- cillus inside the contaminated product turned out to be much more resistant to the preservation system than its isolated counter- part and even more resistant than the commercial strain (Fig. 1). So it seemed that the bacterial re- sistance, emerging in response to the selective pressure of the pres- ervation system, lessened in iso- lation and subsequent cultivation of Lactobacillus. One reason for this decrease in resistance might be that the preservation system was suddenly removed, causing a loss of selective pressure. As a re- sult, the resistant bacteria in the Lactobacillus population lost their former cultivation advan- tage and were gradually replaced by other Lactobacillus bacteria inside the population lacking the burden of a resistance mecha- nism, which can often be energy demanding. This is why in case of an unex- pected contamination of their product, producers should investi- gate and adjust their preservation systems within the contaminated product matrix itself, if possible. Finding a solution 25 years ago Kathon CG (Methyl- chloroisothiazolinone/Methyliso- thiazolinone), formaldehyde or methyldibromo glutaronitrile would have been chosen to ad- just a preservation system after a contamination. Today, however, methyldibromo glutaronitrile is banned from the list of allowed preservatives (Annex V of the Cosmetic Regulation 1223/2009), and formaldehyde and methyliso- thiazolinone are highly restricted in their use concentration and suffer from a bad reputation among the general public. There- fore, the development of alterna- tives is required. prominent contamination germs inside the manufacturing process comprise Enterobacteriaceae, such as Klebsiella pneumoniae or several Enterobacter species3. En- terobacter gergoviae, a faculta- tive pathogenic germ, was found to be the most prominent germ, beside Pseudomonas aeruginosa, in creams analysed in the tropical climate of South Africa4. In the use environment of the end consumer, the contamination risk largely depends on the hygienic conditions but also on the pack- aging type. For instance, the product application using refill packs is like a repeated challenge test. Such conditions are particu- larly challenging for any cosmetic preservation system. Microbiological challenge testing – a case study From time to time we receive ­microbiologically-contaminated products from our customers, all Only salicylic acid combined with the blend of sodium levulinate and sodium anisate led to a significant microbial reduction after seven days CONTAMINATION Microbiological challenges are not restricted to prod- uct application but also occur during the manufacturing process Preservation systems can fail in spite of products having passed microbiological challenge testing This serv amo mat with sham alte out acid nate crob Base han with sues Syna levu late outs agai crob dium In a blen solid prov prod ard also lem sion activ GM men furth The re tions c Fig. 2: Reinforced original preservation system with Dermosoft 1388 inside a natural shampoo formulation CFU: Colony forming unit Fig. 3 teste INGREDIENTS 36  l  COSSMA 7–8 I 2016 www.cossma.com COS1607_34_StraetmansMicrobio.indd 36 26.07.16 16:02 COS1607_34_StraetmansMicrobio.indd 3626.07.1616:02

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