Why are there four cuts on the lid of Becky's milk bottle?

The four incisions you see are reserved positions for hot filling and secondary heating disinfection, in order to let sterile water flow into the gaps of the incisions for disinfection. This incision technology patent comes from Alcoa, which is a disinfection method to realize double insurance. The special filling technology is hot filling, multiple heating sterilization and sterile water disinfection, so the quality and quantity of what you drink can be guaranteed. You can refer to the paper: process design and verification of aseptic filling production line for sports beverage PET bottles.