Serie A's disciplinary tribunal said that around 3,000 of the 5,000 fans in Verona's Curva Sud took part in the chanting, which was "clearly heard in other parts of the stadium", when the Ghanaian had possession of the ball in Milan's 3-1 win.
"Such behaviour is a clear example of discrimination because of race," it added.
Verona, also fined 50,000 euros (39,462 pounds) for the chanting, vehemently denied the allegations.
"We believe that the television pictures are sufficient to refute categorically the biggest non-truth which, today, has been aimed at our glorious club and our glorious fans," said Verona in a statement.
"In over 110 years of history, nobody has ever dared to say anything like this about us.
"No fan, no representative of the police, nor the Milan club, nor the player Sulley Muntari, or media present at the stadium on the day of the day... spoke of such an incident, leaving our club even more perplexed and angry about the action taken."
Inter Milan were fined 30,000 euros because of "insulting chanting aimed at rivals fans based on the region of the country they come from" during the 2-2 draw against Napoli on Sunday, and after laser pens were aimed at the referee.
Juventus substitute Simone Padoin was suspended for his behaviour during the 1-1 draw at Sassuolo even though he never got onto the pitch in Saturday's game.
Padoin was sent off for dissent in stoppage time after he "blatantly contested, from the bench, the work of the referee and the behaviour of the opposing players," said the tribunal in its verdict.
(Writing by Brian Homewood in Berne)
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