Tainted fruit: Federal authorities point the finger at an unsanitary packing plant as the source of the deadly Listeria outbreak this summer. (Ed Andrieski/AP)

UPDATED: 4:30 p.m. Friday, Oct. 21.

If you missed the news reports yesterday, as I did, the Food and Drug Administration determined that an unsanitary cantaloupe packing facility tied to Jensen Farms in Colorado was the source of the deadly Listeria outbreak that killed 25 people this summer.

In Dina ElBoghdady’s report, she noted that federal regulators were still uncertain how the Listeria made its way to the packing plant:

But investigators suggested that it might have been in the soil or on the cantaloupe at levels that were undetectable. They also said a truck that carried culled cantaloupe to a cattle farm might have driven through animal feces and dragged back Listeria on its tires. The truck was parked close to the packing facility.

The New York Times, in its story yesterday, also noted that Jensen Farms had, just days before the outbreak began, passed a safety inspection in which an outside contractor apparently gave the operation 96 out of 100 points.

These stories got me wondering if the Maryland Department of Health and Mental Hygiene had determined where the lone Free State victim had eaten his tainted cantaloupe, given the fruit apparently was never shipped to Maryland. Dr. Clifford Mitchell, assistant director for environmental health and food protection for the state, said today that the traceback has been completed in the case, and the investigation “could not confirm that he had eaten cantaloupe that was part of the recall.”

“The fact that we could not confirm that does not mean that he did not eat it,” Mitchell added. “What it means is that we are limited” in the ability to trace back the tainted fruit.

“We did communicate with the major distributors, and we know for a fact that they went and looked up and down their supply chains and that we did not find any of the officially recalled product in Maryland stores,” Mitchell said. “Is it possible that he obtained a cantaloupe that was contaminated in Maryland? It is possible. Will we know for sure? I think it’s possible that we will never know that for sure.”

Mitchell said that Maryland was only aware of this single Listeria case in the state but noted that “even if you had a number of people who ate potentially contaminated material, not all of them would get sick. It’s the nature of the organism that only some of the people with exposure will get sick.”

Mitchell did not know if the Maryland victim had traveled outside the state to eat the contaminated cantaloupe.