Sanford Nelson has had a two-year crash course in Detroit commercial real estate, with the result being a 142,500-square-foot Eastern Market portfolio quietly acquired over the last 18 months.

Son of millionaire serial entrepreneur Linden Nelson, the 29-year-old has his eyes set on a $20 million effort to buy and improve no fewer than 11 properties in the country's largest public food market. The plan could balloon to $100 million or so, depending on what the father-son team, along with their other investors, do with the properties, including mostly vacant land, they have assembled in that time frame, Linden Nelson said.

The portfolio includes perhaps two of the most well-known buildings in the food district: The building that houses Supino Pizzeria and Russell Street Deli, as well as the Bert's Warehouse building to the north on Russell Street.

While real estate investors have steadily streamed into Eastern Market in the past several years, including a New York City-based company that earlier this week Crain's first reported is planning a large-scale mixed-use development across a block and a half of Adelaide Street nearby, it's important to the Nelsons and their investors that the food district maintain its identity.

Sanford, who went to the University of Colorado at Boulder and then the University of Michigan, says Eastern Market can't turn into a homogenized, watered-down version of itself, as food districts in other major cities have been developed beyond recognition.

"Our biggest thing is our commitment to maintaining what Eastern Market is all about," said Nelson, whose company is called Firm Real Estate LLC, based in Detroit.

"It can't become like some of the other food districts in this country like the Meat Packing District in New York or the Fulton District in Chicago, where it has been redeveloped to the point where the food industry really no longer even exists there. That cannot happen and will not happen in Eastern Market."

Dan Carmody, the president of the Eastern Market Corp. who has been working with the Nelsons on honing their plan, agreed.

"We are painfully aware that other food districts like Eastern Market have disappeared when a tsunami of real estate investment popped in," he said.