Burke’s law firm has won property-tax cuts for the Little Village warehouse, owned by Frank McMahon, that’s home to Windy City Electric and McMahon Food Corp., which has the $20 million-a-year contract to provide milk to Chicago’s schools.

“Ald. Edward M. Burke is a friend of many years,” Frank McMahon’s attorneys say.

Burke declined to comment.

His assistant chief administrative officer at City Hall — Michelle Murphy — is married to Daniel T. Hebert, a business associate of Anthony McMahon and his brother John K. McMahon, a former city of Chicago electrician.

Other politicians the McMahon interests have financially supported the most:

“They’re my cousins, and they’ve been helpful to me,” Birkett says, “just like a lot of other family and friends.”

Since Michael McMahon took office in 2000, the DuPage County Board has awarded more than $722,000 in contracts to McMahon Food and one of its longtime partners, Nick’s Dairy Service, to deliver milk to the county-owned convalescent center and the county government office campus in Wheaton.

Michael McMahon, who isn’t seeking re-election, says he has abstained from voting on those contracts, though county board records show he voted for a $47,800 contract to Nick’s Dairy in February 2011. McMahon says the records are wrong.

Two of Frank McMahon’s daughters — Mary B. McMahon, 32, and Frances J. McMahon, 28 — are assistant state’s attorneys in Alvarez’s office. Both were hired by Alvarez’s predecessor, former State’s Attorney Richard Devine. Mary McMahon, who’s paid $77,100 a year as a prosecutor, and Frances McMahon, who makes $59,500, also are owners of McMahon Food, which also provides milk to the Cook County Jail and the Cook County Juvenile Detention Center.

Alvarez says she met Frank McMahon after she won the Democratic primary race for state’s attorney in 2008 and that she was unaware that Frank McMahon’s two daughters are owners of McMahon Food.