Maryland officials are investigating an unusual prison disappearance. An estimated 25 tons of meat has vanished from a state prison near Hagerstown. Nobody knows where it went, and the baffled local prosecutor has thrown the issue back to prison officials.

A roll of baloney triggered the investigation. The baloney, wrapped and labeled, was found last winter near a bulldozer being used outside the prison grounds for snow removal. That may have uncovered the place where the missing goods were being delivered to someone.

That's the theory. In any event, based on a tip from Warden Marlin Bachtell Jr., state police checked and found that 52,201 pounds of meat and byproducts vanished between July 1, 1981, and July 31, 1982, from the State Use Industries meat-processing plant at the Maryland Correctional Training Center.

The plant processes about 68 tons of meat each month, selling it to 30 state facilities, including nine prisons. About 20 inmates work at the plant, supervised by two journeymen meatcutters who also are correctional officers, or guards.

John Salvatore, state's attorney for Washington County, said the missing food is valued between $3,000 and $100,000, depending upon whether it is processed meat or such byproducts as bone or fat.

"My personal opinion is that it is . . . largely. . . meat" valued at about $2 a pound, said Salvatore.

Salvatore's conclusions: " . . . minimally gross mismanagement and incompetence" and record-keeping that is "either a sham or a shambles." He recommended that three unidentified prison aides be disciplined administratively.