Why does the hand soap used in the Mi Automatic Soap Dispenser turn yellow after a long time?

The official standard antibacterial hand soap is a light yellow liquid containing the effective antibacterial agent PCMX. Over time, the antibacterial agent will naturally turn yellow, which is normal and does not affect its antibacterial efficacy. The formula contains a significant amount of natural plant-based ingredients and no artificial colorants, so you can use it with confidence.
For your reference, here are more details about the official standard hand soap:
1. The antibacterial hand soap consists of water, surfactants, para-chloro-meta-xylenol (PCMX), and fragrance;
2. The amino acid foaming hand soap is composed of water, amino acid surfactants, moisturizers, emollients, and fragrance;
3. The antibacterial hand soap has a shelf life of two years, while the amino acid foaming hand soap has a shelf life of three years.