The fourth case of bovine spongiform encephalopathy (BSE), or mad cow disease, in the U.S. was confirmed by the U.S. Department of Agriculture (USDA) in a dairy cow carcass from Tulare County on April 24. The infected animal did not enter any human food, according to the USDA report, and the dairy in question along with another related dairy are under quarantine.
This case isn’t a cause for concern, according to animal science professor Robert Delmore, because of the low number of cases seen today and the protocols in place to prevent it from spreading.
“People don’t need to be afraid,” Delmore said. “I tell them in my class, ‘I’d be worried about a lot of other things before even remotely worrying about this.’”
BSE develops because of abnormally-folded proteins called prions in the brain, said Dr. Michael Lyon, a veterinarian at the Large Animal Practice veterinary clinic in San Luis Obispo. It spreads when cattle ingest feed containing those prions from an infected cow’s tissues, Lyon said — primarily the central nervous system. These materials are called “specified risk materials.”
According to a statement, from the USDA’s Chief Veterinary Officer John Clifford on April 24, this case of BSE was found during “our targeted surveillance system” and determined to be atypical — “a very rare form of the disease not generally associated with an animal consuming infected feed.” Clifford’s statement also said the USDA will conduct “a comprehensive epidemiological investigation in conjunction with California animal and public health officials and the FDA” to look into the case.
For Delmore, this atypical case is favorable.
“If you have to have a case of BSE, it’s better,” Delmore said. “It’s not a case where someone did something wrong.”
And this case doesn’t change anything, Delmore said. The USDA has also tested the cow’s offspring, which was found negative for BSE. Since BSE can only be transmitted through infected feed, Delmore said the steps the USDA has taken were “in an abundance of caution.”
This news also won’t change anything about the way Cal Poly produces its beef at the soon-to-be-open meat processing center, Delmore said. The center will follow federal regulations for harvesting cattle and dealing with the specified risk materials — and it already refrains from using meat and bone meal for cattle feed. The USDA has to be present whenever cows are harvested, Delmore said, and will be there when Cal Poly’s animals are harvested.
Until 1997, meat and bone meal containing materials from cows was allowed to be fed to other cows in the U.S., but that year the FDA enacted a ban on the practice to reduce the risk of the disease spreading — and “virtually every country in the world” has taken the same kind of action, Delmore said. That ban also outlawed those materials from being put into products sold and consumed by humans.
Because of the safeguards put in place, Lyon said a case of BSE would ideally occur as a mutation in one cow and end there, with no way for it to spread — and the odds of people being infected are unlikely. He said there are other foodborne illnesses, such as salmonella, he would worry about more than mad cow disease.
Thirty-five million cows are harvested each year in the United States, according to Delmore — some grown specifically for meat, while the rest are dairy cows. BSE is seen in cows older than 30 months, Delmore said. Dairy animals are typically younger than beef cows when they are harvested, he said, but that doesn’t mean beef cows are more at risk for BSE.
Cal Poly’s dairy cows shouldn’t be a source of worry for consumers either, because BSE can’t be transmitted through milk, Dairy Science Club President Nick Southfield said. This case was a mutation, he said, not an issue of food safety or the result of a mistake. But Southfield said it’s still cause for concern because it could happen again.
However, he said the government has good protocols in place to react to this situation — implementing the quarantine and making sure no other cows were infected.
“It’s an isolated incident, and it was contained and it still is being contained,” Southfield said. “They’re doing more than enough to contain the problem.”
Unfortunately, not all consumers know that dairy products are safe from BSE, Southfield said, and this occurrence shows students at Cal Poly that the dairy industry needs to be better at educating consumers about the facts.
While it’s highly unlikely that a cow at Cal Poly would be at risk for BSE because of the small number of animals here, Delmore said, if an animal were to show any symptoms, it could be tested by the USDA. There isn’t any screening test for BSE, Delmore said, so the USDA can’t test an animal until it develops visible symptoms.
This case of BSE doesn’t trouble agricultural communications professor Scott Vernon either — he said it is natural.
“When we’re dealing with food, it’s a natural product and it has some natural enemies,” Vernon said. “Where BSE might show up in the future no one can predict.”
And Vernon was impressed by the industry’s reaction to this case — he said they did an excellent job communicating with the media, government and consumers. Vernon also echoed Delmore’s confidence about the safety of Cal Poly’s meat processing practices after this newest case of BSE. The opening of the unit will be “under quite a bit of federal scrutiny,” he said, and students will be trained on how to safely process and handle meat.
However, Vernon also said consumers are partly responsible for food safety as well. He advises consumers to be more careful about how they handle food and inform themselves about food safety issues.
The numbers of BSE are continuing to decrease, Delmore said — to the point where it almost can’t be measured. It would be a stretch for meat and bone meal to be out there, Delmore said.
“At the end of the day, I still have to come back to the numbers,” Delmore said. “This is one animal. Anytime any animal has it we’re unhappy with it, but this doesn’t change our at risk.”