The Norwegian Scientific Committee for Food Safety (VKM) was asked by the Norwegian Food Safety Authority to do a risk assessment regarding development of resistance in microorganisms resulting from the use of QACs in cosmetic products. The panel concludes that the contribution to increased occurrence of resistance to clinically important antimicrobial agents by QACs in cosmetic products cannot be excluded.
An ad hoc working group of experts was appointed with the mandate to draft an assessment regarding this issue.
The fields of application of quaternary ammonium compounds (QACs) are wide ranging.
In cosmetic products, QACs are added as preserving agents, due to their ability to condition hair and/or their claimed effects on skin, nails or lips.
The most important QACs in cosmetic formulations are benzalkonium chloride, stearalkonium chloride, cetrimonium chloride, cetrimonium bromide and cetylpyridin chloride.
It is evident that resistance towards QACs is widespread among a diverse range of microorganisms, and that microbial resistance to QACs is facilitated by several mechanisms. Currently, available literature on development of resistance due to QACs in cosmetics is lacking.
However, it is likely that QACs in such products will add to the selection pressure towards more QAC resistant microorganisms among the skin and mouth flora.
Furthermore, there is increasing evidence of co-resistance and cross-resistance between QACs and a range of other unrelated antibacterial agents such as antibiotics and disinfectants. Thus, the contribution to increased occurrence of resistance to clinically important antimicrobial agents by QACs in cosmetic products cannot be excluded.
The VKM Panel on Biological Hazards was responsible for this risk assessment.