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In the case of high concentrations of surfactants, such as shampoo, it is difficult to evaluate the microbial limit. The reason is that the neutralizers does not completely neutralize the shampoo. The purpose of this study is to find a dilute medium that is completely neutralized even in formulations containing high concentration surfactants. Most of them failed when evaluated by the ISO standard test method. However, when MLA medium was used instead of TSA, neutralization was confirmed except for some bacteria and formulations. It was confirmed that the acceptance rate was increased when tween and lecithin were added to the neutralization medium (MLB). In particular, it was confirmed that TSA neutralized over a certain level. In conclusion, in the case of a formulation with a high concentration of surfactant, it is suggested to use MLB with Tween80/lecithin= 4%/1% as a neutralization medium and to use MLA as an …