Between his responsibilities as Cook County assessor and preparing for a possible re-election battle, I would have thought Joe Berrios had his hands full these days.

That’s why I was surprised when I received a photo of Berrios taken this past week at the Global Gaming Expo in Las Vegas.

What, you might wonder, was the theoretically full-time Cook County assessor doing at the nation’s premiere casino industry convention with a lanyard around his neck?

As it turns out, Berrios was there on behalf of the Illinois Gaming Machine Operators Association, an important client of his longtime lobbying business, B-P Consultants Inc.

The association, which is the trade group for the state’s video poker industry, scheduled a series of receptions in Las Vegas in conjunction with the convention. One purpose was to schmooze with a group of Illinois legislators in attendance.

In the five years since video gambling in bars and restaurants was legalized in Illinois, the industry has exploded with 27,649 machines at 6,266 locations — the equivalent of 23 new casinos. In other words, it’s a big business with important legislative concerns.

The assessor, who also serves as chairman of the Cook County Democratic Party, attended most of the group’s convention events but says he didn’t engage in any lobbying.

Berrios promised to give up lobbying when he was elected assessor in 2010, but there was an asterisk: he didn’t promise to give up the lobbying business. Accordingly, he continues to profit from it.

B-P Consultants is a partnership between Berrios and Sam Panayotovich, his friend from when they both served together in the Illinois Legislature.

Berrios has a 49 percent stake in the business, according to his publicly-filed Statement of Economic Interest.

In a flyer welcoming the lawmakers to Las Vegas, Gaming Machine Operators Association executive director Ivan Fernandez listed Berrios and Panayotovich as members of “IGMOA’s Team.”

IGMOA is just one of B-P Consultant’s clients. The firm also represents the Illinois Licensed Beverage Association (businesses that need liquor licenses and often offer video gambling), Illinois Automatic Merchandising Council (the vending industry), Comcast and tobacco giant Altria.

Berrios told me in a telephone interview Friday he has kept his promise to quit lobbying. The legislators with whom I spoke agreed he did not lobby them.

Berrios said Panayotovich handles the lobbying chores.

“My basic job is to keep the books and such,” said Berrios, an accountant by training. “Ninety-nine percent of the stuff goes through Sam.”

I told him that was a neat trick: getting 49 percent of the profits while doing only one percent of the work.

He jokingly accused me of trying to cheat him out of his fair share, noting he brought in some of the firm’s clients, including the gaming machine operators.

Berrios said he would have sold his share of the business to Panayotovich if he could have, but “he couldn’t afford to buy me out.”

Berrios said he arrived in Las Vegas on Sunday and left Wednesday. A big fan of country music, Berrios said he had “really wanted” to go to the concert Sunday night where 58 people were killed in a mass shooting, but kept a dinner engagement instead.

“I was ticked off I couldn’t go. The Lord was looking down on me,” he said.

Berrios emphasized he did not bill the county for his travel and saw the trip partly as vacation. As an elected official, he doesn’t have to schedule vacation time like a regular employee.

I spoke to three of the nine legislators in attendance, each of whom said they paid their own way on the trip.

I believe Berrios is totally within his legal rights to keep his side business while serving as the $125,000-a-year assessor.

But the voters of Cook County should see it as one more good reason to question whose team he’s on.