After two years of research, health investigators have reported that slaughterhouse workers that suffered debilitating diseases of their nervous system were exposed to microscopic particles of pig brain.
The disease was first reported in a dozen workers in a pig processing plant in Minnesota and later in 10 other slaughterhouse workers in an Indiana abattoir.
The Centers for Disease Control cautioned more than two dozen other U.S. operations processing porcine brains to stop using compressed air to remove the brain from the skull.
The plant in southern Minnesota processes about 18,000 pigs a day and has 1,200 workers.
The plants prove the truth of the saying that there is a use for everything on the pig but the oink; nothing goes to waste in the plants, including ears, entrails and bone.
The workers who were diagnosed with neurological illness all worked in sections of both plants where the pig’s severed heads are processed.
The sick workers – all Latinos and between 28 amd 52 years old – were assigned to the operation that removed the pig’s brains. Unlike almost all the other U.S. plants, the Minnesota and Indiana operations used high-pressure compressed air to remove the tissue.
The CDC’s disease detectives reported in the International Journal of Occupational and Environmental Health that the high-pressure air guns used to remove the brain matter most likely aerosolized the brain material into tiny particles, which the workers inhaled.
Federal investigators said masks and other personal protective equipment were being used.
All of the sick workers showed symptoms that ranged from gradually progressive weakness to acute paralysis. The illnesses were diagnosed as Immune-mediated Polyradiculoneuropathy or IP. This involves the peripheral nervous system, the intricate communications network that transmits information from the brain and spinal cord to other parts of the body.
In IP, many nerves are affected, which can result in severe pain, crippling weakness, numbness, or difficulty controlling specific muscles.
“Basically, we found several IP cases in the Indiana plant with work-related risk factors that were similar to what was observed in the Minnesota plant,” said Lt. Jennifer Adjemian, an epidemiologist with the U.S. Public Health Service and the principle investigator for the study.
“This further supports the theory that this mechanism of brain extraction was leading to the development of IP, a new neurological illness.”
Adjemian said that no new cases have been brought to CDC’s attention since the meat processors ceased using pressurized air guns.
One of the lingering questions is: Were the brains of the pigs diseased?
The swine had passed inspection by the U.S. Department of Agriculture Food Safety and Inspection Service, and the investigation had not identified any food-borne risk to the general population, the investigators said.
Here is a link to the study in IJOEH.