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White spots in meat a sign of TB – but thorough cooking can make it safe


  • A WhatsApp message advises people to avoid eating meat with bubbles and white spots because it’s a sign of animal tuberculosis, and very dangerous.

  • The photo in the message is of an American white-tailed deer infected with bovine tuberculosis.

  • TB doesn’t usually infect the muscle tissue of meat we eat, and infected meat is unlikely to be sold in mainstream shops. Experts say there are simple precautions people can take to kill bacteria in meat and organs.


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“If you see bubbles and white spots in animal meat, please avoid eating it. It is animal TB and very dangerous.” TB is the bacterial disease tuberculosis.

This advice has been shared on WhatsApp in South Africa. It includes a photo of what seems to be a raw ribcage covered in white spots. 

“Please share widely in your groups.” 

The photo and message have also been shared on Facebook and Twitter

Do these “bubbles” and “white spots” indicate tuberculosis in meat that can infect people if they eat it? We investigated. 
 

Photo shows ribcage of white-tailed deer


A reverse image search of the WhatsApp message found several websites that credited the photo to the Michigan Department of Natural Resources in the US.

Prof Dan O'Brien, a veterinary specialist at the department, confirmed that it was their photo. It shows the ribcage of a white-tailed deer infected with bovine tuberculosis (bTB). 

He said that the description in the WhatsApp message was not entirely accurate: the "lesions pictured are not bubbles, they are small, solid abscesses”.
 

People can be infected with bovine TB


There are different types of TB. The main type that affects people is caused by the bacteria Mycobacterium tuberculosis, explains the World Health Organisation.

It mostly affects the lungs and is spread from person to person when people cough, sneeze or spit.

But it’s important to know the difference between human TB and bovine TB, Dr Anita Michel from the Department of Veterinary Tropical Diseases at the University of Pretoria told Africa Check. 

“Human TB is transmitted between people and bovine TB is transmitted between cattle or from cattle to other animals or humans.” Bovine TB is caused by a bacteria called Mycobacterium bovis.

People can be infected with bovine TB by coming into contact with infected cattle or by eating parts of an infected animal, O’Brien said. Another common cause of infection, particularly in children, is drinking unpasteurised cow's milk.

Michel told us that when people fall ill with human TB or bovine TB, the “symptoms are indistinguishable and can present as pulmonary [human] TB”. Drinking contaminated milk could cause “an inflammation of the lymph nodes, most commonly in the neck area”. 
 

Bacteria typically infects lymph nodes, lungs and organs


Prof Michele Miller, who has a PhD in veterinary immunology and leads research on animal tuberculosis at Stellenbosch University, told Africa Check that bovine TB was unlikely to infect meat. 

“Meat is usually skeletal muscle and the mycobacteria don’t typically infect this type of tissue – it is more common in lymph nodes, lungs, and organs such as liver, spleen.”

O’Brien from the Michigan Department of Natural Resources said the same about the white abscesses in the WhatsApp message: it’s “essentially never seen in the actual [muscle tissue] of the deer that people would typically eat”.

Michel said regulated meat inspections meant it was “highly unlikely” that meat infected with bovine TB would be sold in South Africa’s formal meat markets. 

But there is a risk for people who keep and slaughter animals at home. She said in these cases, there was a chance that people could get bovine TB by eating raw or undercooked organs or drinking infected milk. 
 

Meat and milk should be cooked properly


People should still be wary of eating meat with spots or bubbles, Miller cautioned. 

“White spots can be associated with a wide number of different conditions besides TB,” she said. “It would be unwise to eat any meat that has bubbles and white spots regardless of what caused it.”

Experts say there are simple precautions people can take to kill bacteria in meat and organs. Miller said meat should be cooked to an internal temperature of at least 60 degrees celsius. But she advised that this may “depend on how many bacteria are present” and “where they are located”. 

Temperature affects how long milk should be boiled to make it safe. 

Miller explained that milk heated to 63 degrees celsius should be boiled for at least 30 minutes. But milk that reaches a temperature of 100 degrees celsius only needs to be boiled for a second. 
 

Conclusion: Yes, white ‘spots’ in meat can be a sign of animal TB


A photo and message shared on WhatsApp, Facebook and Twitter warns that people should avoid eating meat with white bubbles or spots because they’re signs of animal tuberculosis (TB).

A reverse image search revealed that the photo shows the ribcage of a American white-tailed deer infected with bovine TB.

Experts said people can get bovine TB by eating raw or undercooked organs from infected animals or by drinking unpasteurised cow's milk. But they’re unlikely to get bovine TB from meat sold in formal markets.

If you’re unsure about the meat or internal organs that you are about to eat, thoroughly cook the meat at a higher temperature. Unpasteurised milk should be boiled to make it safe to drink. 

Further Reading