Signs instruct employees, customers and the U.S. Postal Service how to make contact with Ron's Produce Co. Locked and chained gates greeted visitors Friday at the warehouse.

The 19 trucks in Ron's Produce Co.'s fleet sat behind locked gates at the company's south-side warehouse on Friday, a day after the longtime Tucson produce distributor notified restaurants it would no longer be doing business.

A note on the gate gave employees a phone number to call about returning their uniforms. The 60 employees also learned of the closing on Thursday, company founder Ron Sternberg said.

The closing came as a result of Sternberg's decision to retire, something he said he had been considering for some time.

"It was a family decision. We wanted to get a chance to enjoy our time together as a family," said company vice president Sam Sternberg, one of Sternberg's two sons who ran the company.

Neither man would say when the decision was made. Ron Sternberg said the company is liquidating its equipment, vehicles and 24,000-square-foot warehouse, ending a 35-year run supplying mostly smaller Tucson restaurants with fresh produce.

Two callers to the Star said an attempt by employees to unionize resulted in the owners shutting the company down.

Ismael Garcia worked as a truck driver for the company for three years until he was fired last month. The reason he was given was insubordination, but Garcia thinks it had to do with union activity.

"Apparently, they (management) heard some talk in the warehouse of union activity, and management had talked to a few employees and they said that my name was mentioned," Garcia said Friday evening.

He wasn't the only employee interested in unionizing, he said. Other employees thought they were mistreated by management and not respected, Garcia said. Anyone who complained to management was sent home without pay.

"Nobody would complain because they were afraid to get sent home," he said.

When asked about union activity in the warehouse, Sam Sternberg said he was unaware of any such discussions and would not comment further.

Restaurant owners said they had long relationships with Ron's.

"The best part about Ron's … was that they were local. If we needed something we could get it," said Jim Murphy, who has ordered produce from the company six days a week for the last eight years for his northwest-side restaurant, Bluefin Seafood Bistro. He also owns Kingfisher on East Grant Road.

"The advantage to us to have a local produce company is that at 10 o'clock at night I can call my order in and run it as close as possible so I don't have old produce," said Jonathan Landeen, chef-owner of Jonathan's Cork on East Tanque Verde Road, who relied on Ron's for weekly deliveries of specialty produce for the past dozen years.

Murphy had a long history with Ron's that dated to the 1980s, when Murphy was the chef of the now-closed Jerome's. He could always rely on the company to come through with specialty produce items that weren't available from his primary food distributor.

When he struck out on his own with Kingfisher and then Bluefin, Murphy continued his relationship with the company. Recently, though, Ron's has run short on produce and there had been issues with getting some items, Murphy said.

Landeen said he got his last order from Ron's early this week. "I got two cases of corn from them on Tuesday or Wednesday and it looked fabulous," he said. "We've been buying from Ron's a long time. We had a good relationship."

With Ron's out of the market, some restaurants might lose what Merit Foods of Arizona General Manager Scott Butler calls a niche service.

"Nobody in town anymore can deliver $50 or $60 worth of produce a day, six days a week. That's gone," said Butler, whose company will not deliver an order unless it is a minimum of $200. "You either have to keep raising your minimum drops or you are just not profitable."

Reporter Kimberly Matas contributed to this article. Contact reporter Cathalena E. Burch at cburch@azstarnet.com or 573-4642.