Changes Over Time in Number of Bacteria and Usage Experience in Refillable Lotion

Abstract

  Refillable cosmetics are widely used to save resources. However, there are no clear standards regarding the expiry date of cosmetics that are repeatedly refilled. In this study, we investigated the number of viable bacteria in refillable lotion and changes in the usage experience. Six types of lotions were used in this study. It was found that unused lotion inhibited the growth of added staphylococci. Furthermore, in a 6-month storage test of unused lotion, no viable bacteria or coliform bacteria were detected. A monitoring test using these cosmetics was then conducted for 6 months, during which time each monitor used the same lotion daily and refilled the bottle once a month. After the six-month period, no viable bacteria, coliform bacteria, or Staphylococcus aureus were detected in the lotion remaining in the bottle. In the questionnaire survey, there was almost no change in the usage experience of the lotion.