How does the property department monitor the work of cleaners and the prevention and control of cleaning aunts, and the disinfection method is invisible to the naked eye?

Our property cleaners stare at the garbage sorting next to the trash can every day. When the property manager is away on weekend nights, the cleaner is just putting on a show. Every class will send some photos of trash cans to the group before going to work, which is easy to cheat. Now the handover is done online with Mark watermark camera, and the photos must be taken in several trash cans. If you have time to take photos, you can see them clearly and you can't cheat.