No vegetables, fruit or other produce have been hurled on stage at members of Chicago during their summerlong tour playing big-band music.

That’s enough validation for Walt Parazaider.

“I don’t see any tomato stains on my stage clothes,” the original reeds player said jokingly during a recent stop in Portland, Ore. “We’re playing half of our ‘Night & Day’ album in the show. What’s great is, once fans have heard it, record sales go up after we go into each town.”

“Night & Day,” Chicago’s 22nd album and the first for Giant Records, is a natural progression for the rock stalwarts. The band’s jazz-oriented background is well-suited for the lost art of big band.

“I haven’t read one negative review about what we’ve done,” Parazaider said. “This isn’t something we’ve done on a whim. We’ve all enjoyed big-band music. This isn’t entirely what we’re all about, but it shows a side of us that’s important to us.”

Also important to the group – which features four of the six original members – are children’s charities.

When the No. 24-rated Notre Dame football team takes the field Sept. 23 against Texas (minus the recuperating head coach Lou Holtz), Chicago will be on the sidelines as the marching band plays a medley of the big-band tunes that appear on “Night & Day.” Afterward, Chicago will play a benefit concert at Notre Dame’s Joyce Center.

The cause? The Ara Parseghian Medical Research Foundation, which funds research for the rare and fatal genetic children’s disease, Niemann-Pick Type C. Parseghian, who coached the Fighting Irish in the 1970s, has three grandchildren afflicted with the disease.

“How can you turn your back on children when lives are at stake?” Parazaider said. “This is for a very good cause. We want to be there for Coach Parseghian.”

Members of Chicago are no strangers to the Notre Dame football legacy: one of the group’s managers in the ’70s played for Parseghian. In 1974, the coach gave the band permission to watch a game from the sidelines.

“It was Notre Dame against USC,” Parazaider said. “I remember it well. I remember thinking, ‘These kids are monsters. They’re huge.’ Then you see them on the sidelines, crying over a mistake and you realize they’re basically young kids with a set of nerves.

“Notre Dame dominated the first half, and then in the second half, Anthony Davis took the kickoff for a touchdown and the rest was history.”

The night before the Notre Dame-Texas tilt, Chicago will appear at a pep rally and “hopefully we’ll get to rub elbows with the players again,” Parazaider said.

There’s a correlation between football teams and rock groups, he said.

“Our band is a lot like a team, in that it’s a democracy,” he said. “As far as a leader, we’ve never really had one. Everyone has their fortes and they’re allowed to express themselves. That’s probably why we’ve lasted this long.

“This band has toured for 29 years without a break. We’re entering our 30th year together, and we’re proud of that.”

BWF (before we forget): Chicago’s discography of Top-10 singles – “Make Me Smile” (1970); “25 or 6 to 4” (1970); “Does Anybody Really Know What Time It Is?” (1970); “Beginnings/Colour My World” (1971); “Saturday in the Park” (1972); “Feelin’ Stronger Every Day” (1973); “Just You ‘N’ Me” (1973); “(I’ve Been) Searchin’ So Long” (1974); “Call On Me” (1974); “Old Days” (1975); “If You Leave Me Now” (1976); “Baby, What a Big Surprise” (1979); “Hard to Say I’m Sorry” (1982); “Hard Habit to Break” (1984); “You’re the Inspiration” (1984); “Will You Still Love Me?” (1986); “I Don’t Want to Live Without Your Love” (1988); “Look Away” (1988); “You’re Not Alone” (1989); “What Kind of Man Would I Be?” (1989).