Replays showed Suarez apparently biting the shoulder of the defender as the pair clashed in the Italian penalty area. Chiellini then pulled back his shirt to show a bitemark as Suarez lay on the ground clutching his mouth.
Uruguay scored a minute later to qualify for the knockout phase and send Italy home.
After the match Fifa confirmed it had lauched a probe into the alleged bite.
Chiellini said “. . . not sending off Suarez [was] ridiculous. It was absolutely clear. There’s even a mark.”
It is the third biting incident involving Suarez. He was banned for seven matches in 2010 after biting PSV Eindhoven player Otman Bakkal in a league match when he played for Ajax. With Liverpool, he bit Chelsea’s Branislav Ivanovic in 2013 and was banned for ten games.
Uruguay Coach Oscar Tabarez said he didn’t see the alleged bite and repeatedly declined to comment.
He said: “If it happened the referee probably didn’t see it.” Tabarez also defended his star striker, saying “Suarez, besides the mistakes he might have made, is the preferred target of certain media.”
A Fifa spokesperson said: “We are awaiting the official match reports and will gather all the necessary elements in order to evaluate the matter.”
Fifa’s disciplinary code sets a maximum ban of 24 matches or two years, but the longest ban in World Cup history was eight games for Italy’s Mauro Tassotti for breaking Spain’s Luis Enrique’s nose in 1994 with an elbow. Zinedine Zidane got a three-match ban for headbutting Marco Materazzi in the 2006 final.