Fatal germ found on production line at dairy
A germ that killed three people and sickened two others originated on the production line of a mom-and-pop dairy in Shrewsbury, state disease investigators reported yesterday as they provided the clearest evidence yet of how milk became contaminated with the lethal bacteria.
Tests performed on the Whittier Farms plant found a strain of listeria on the floor that was identical to the type found in people who became ill last year after drinking the dairy's milk. Investigators discovered the germ near a key piece of equipment used after milk is pasteurized.
"Finding it in the environment there closes the final loop," said Dr. Alfred DeMaria, the state's director of communicable disease control. "This was a totally unique strain."
That same strain was also identified in seven unopened containers of milk the state removed from a retail store adjacent to the Whittier Farms production facility. The germ was found in skim milk as well as coffee-, chocolate-, vanilla-, and strawberry-flavored milk.
The review of the Whittier production line also discovered unrelated strains of listeria in a drain, an unwashed bottle, and another piece of equipment.
State investigators said they were unsure how listeria made its way inside the Whittier plant, which had received good marks in earlier inspection reports.
Perhaps workers carried it on their clothing or shoes from elsewhere on the farm, said Suzanne Condon, the top environmental health official at the state Department of Public Health. Another possibility: Spray hoses used for cleaning might have disseminated the germ.
Investigators said it was also unclear how the amount of listeria isolated at Whittier compared with other dairies. "The level of scrutiny that this particular facility is receiving now is far beyond what typically happens based on state and federal regulations," Condon said.
Whittier Farms agreed to halt production in December, after authorities first linked it to the cases of listeria. Condon said the dairy will be allowed to resume production only after ensuring it can safely produce milk, which was sold mainly in Worcester County.
"There are going to be things that will be required of this plant that go far beyond what would be typically required because of what we found," Condon said.
The owners of Whittier Farms did not return a phone message left yesterday. 