All files changed in last 10 minutes. That would be normally. If more than 10min, your SD card is dead.
Do a proper shutdown. If you want to avoid fs corruption in any stage, you need to have full read only file system. This is ofc possible, but it has other limitations - you can't write to it
You can change commit interval from 10m to 0m but it will affect performances. Go to /etc/fstab and remove commit=600 but this will solve only one problem. You still can run into fs corruption due to sudden power cut.