Zhang Wenhua , former Sanlu chairwoman and general manager , pleads guilty . Former Sanlu executives accused of producing and selling substandard products . Scandal revealed after babies using baby powder developed kidney stones . Victims of tainted baby formula to be compensated by 22 Chinese pharmaceutical firms .
Tian Wenhua , former Sanlu chairwoman and general manager , pleads guilty . Four Sanlu executives accused of producing and selling substandard products . Scandal revealed after babies fed milk powder developed kidney stones . Victims of tainted baby formula to be compensated by 22 Chinese dairy firms .