Immigration Minister Cecile Kyenge was speaking at a Democratic Party (PD) rally on Friday when an unidentified spectator threw bananas at her, missing the stage but sparking reactions of disgust from across the country.
Shocking cases of abuse have multiplied against Kyenge, an Italian citizen born in the Democratic Republic of Congo, climaxing earlier this month with a member of the anti-immigration Northern League party who likened her to an orangutan.
Kyenge, who has refused to rise to the bait or write Italy off as racist, immediately reacted to the banana attack by slamming it as "a waste of food".
Social networks lit up with reactions, and ministers and politicians took to Twitter to voice their anger and support for Kyenge.
Italy's environment minister Andrea Orlando expressed "utter indignation for the wretched act", while the agriculture minister, Nunzia De Girolamo, said "Kyenge has shown that faced with idiotic and violent acts, sometimes the best weapon is irony."
At a rally for the Left Ecology and Freedom (SEL) party on Saturday, where she was received with warm applause, Kyenge said she was "proud to be Italian."
"I do not believe the problem lies with me. There are some people who are not happy, who are showing their discontent, and it is my job to listen to that discontent," she told journalists. "I have to draw out the better side of Italy."
Supporters called for Kyenge to stand firm and continue the fight to eradicate racism.
Tensions were running high even before the banana incident, after members of the country's right-wing Forza Nuova association left life-size dolls doused in fake blood at the rally.
The group was protesting over Kyenge's campaign to help children born in Italy to foreign parents obtain citizenship more easily.
Forza Nuova denied it had anything to do with the fruit incident.
Italy, which for decades was a land of emigration, has relatively little experience in dealing with immigration.
While millions of Italians fleeing poverty emigrated to the United States, Latin America and other parts of Europe throughout the 20th century, the Mediterranean country has only had to absorb large numbers of immigrants over the past 20 years or so, mainly from Africa.