(1) Look at the appearance first. Normal pig liver has a shiny surface and a uniform purple color.
(2) Touch by hand. It feels elastic, and it is normal pig liver, without lumps, edema and swelling. In addition, some pig livers have small white spots the size of rapeseed, which is a muscle phenomenon of self-protection after pathogenic substances invade the body. Cut off the white spots and you can still eat them. Don't buy too many white spots.