ST. PAUL, Minn. – On the slaughterhouse floor at Quality Pork Processors Inc. is an area known as the “head table,” but not because it is the place of honor. It is where workers cut up pigs’ heads and then shoot compressed air into the skulls until the brains come spilling out.
But now the grisly practice has come under suspicion from health authorities.
Over eight months from last December through July, 11 workers at the plant in Austin, Minn. – all of them employed at the head table – developed numbness, tingling or other neurological symptoms, and some scientists suspect inhaled airborne brain matter may have triggered the illnesses.
The use of compressed air to remove pig brains was suspended at Quality Pork earlier this week while authorities try to get to the bottom of the mystery.
“I’m still in shock, I guess,” said 37-year-old Susan Kruse, who worked at the plant for 15 years until she got too weak to do her job in February. “But it was very surprising to hear that there was that many other people that have gotten this.”
Five of the workers – including Kruse, who has been told she may never work again – have been diagnosed with chronic inflammatory demyelinating polyneuropathy, or CIDP, a rare immune disorder that attacks the nerves and produces tingling, numbness and weakness in the arms and legs, sometimes causing lasting damage.
New cases of CIDP occur at the rate of one or two per 100,000 people each year, according to Dr. P. James B. Dyck of the Mayo Clinic.
State health officials said there is no evidence the public is at risk – either from those afflicted or from any food leaving the plant, which supplies Hormel Foods Inc.
The working theory from two Mayo Clinic neurologists treating the workers: Exposure to pig brain tissue scattered by the compressed air triggered the illnesses.
“As we’ve investigated these patients, we have information that suggests very strongly that the immune system is activated very strongly in a very compelling way,” said Dr. Daniel Lachance.
Compressed air could turn some brain matter into a mist that could be inhaled, said Mike Doyle, a microbiologist who heads the University of Georgia’s Center for Food Safety. Or workers may have come into contact with something dangerous and then touched their noses or mouths, he said.
Scientists have yet to figure out if there is something in the brain matter that could be causing the symptoms.
“The hard part will be identifying the causative agent and associating that with the animal, showing that the animal carries it,” Doyle said.
Minnesota Health Department spokesman Doug Schultz said the agency is looking into the theory but has not ruled out other causes. Kruse said the company has harvested pork brains on and off for years, depending on demand, but it’s not known why workers began getting sick recently.
Quality Pork has not said what it does with the pork brains. Sold fresh and in cans, pork brains are fried and eaten in sandwiches or gravy in some parts of the country. But it is a small market, and the American Meat Institute, which represents most of the nation’s pork processors, does not track sales.