Health officials have added two new foods to the list of items that tested positive for bird flu.
Cottage cheese and sour cream, as well as one in five grocery store milks, have tested positive for H5N1 particles in recent days.
But ground beef, infant formula and powdered milk gave negative results, in a hopeful sign for mothers and meat lovers.
The FDA said, however, that the virus detected in the products was “inactive” or dead, meaning it did not pose a risk of infecting humans.
It comes as veterinarians warn that more people on farms are likely to have been infected with the virus after hearing reports of sick workers on cattle ranches that have recorded outbreaks.
A tick indicates foods that tested positive for bird flu, while a cross indicates those that were tested for bird flu but were not found to contain the virus.
Dr. Barb Petersen, who works in the Texas region at the center of the outbreak, said almost every farm with sick animals she had visited also had sick people.
“It was just a surprise,” he said. Fortune‘I was just a little [in] disbelief.
‘We were actively controlling the humans. There were people who never missed work, they missed work.’
His words echo those of other veterinarians, including one in Wisconsin, who said he had also heard reports of sick people on infected farms.
Only one person has tested positive for the virus this year: a farm worker who came into close contact with infected livestock. The CDC has tested 25 other people, all of whom were negative, and says about 100 people are being monitored.
The map above shows states that have reported bird flu infections in livestock herds.
The FDA did not disclose the brands of foods it tested and found to contain the bird flu virus.
But he did say the claim was based on 297 dairy or cow products purchased at grocery stores in nine states that were experiencing outbreaks in livestock.
In a separate statement, the USDA also revealed the results of its testing of 30 ground beef samples, and none were found to contain the virus.
This follows separate tests last week on 96 grocery store milk samples, which found one in five contained the virus.
Officials also conducted egg inoculation tests to establish whether the virus found in food was still active and could infect humans.
This is where a small amount of H5N1 particles from the products are injected into a fertilized chicken egg which is then monitored for changes that would suggest an infection, such as cell death.
But no changes were detected in the eggs in the experiments, which authorities said showed that the products, although containing fragments of H5N1, were still safe to eat.
The FDA says pasteurization, where milk is heated and cooled rapidly to kill viruses, eliminated viruses and made the products safe to consume.
Other foods such as butter, ice cream and cakes were not tested for bird flu virus particles.
Dr. Donald Prater, acting director of the FDA’s Center for Food Safety and Applied Nutrition, said that in all cases, the virus had been eliminated by pasteurization and therefore posed no health risk.
But some scientists have expressed concern about consuming milk that could contain fragments of bird flu, saying they still want to see more data.
Dr. Rick Bright, a virologist and former director of the Department of Health and Human Services who previously expressed concern about the presence of the virus in milk, said the initial data was “reassuring.”
‘Each new data remains reassuring for pasteurized dairy products.
‘[But] The data are preliminary and many critical experiments remain pending. And everything is a snapshot in time. “As the outbreak spreads to more farms, more viruses can enter the system.”
So far, a total of 36 farms in nine states have reported bird flu among their livestock, and some experts express concern that the outbreak may be more widespread.
The cattle were reported to have been lethargic and had produced milk that was slightly off-color. The virus has been detected in milk and lungs in previous cases.
Experts say workers could become infected with H5N1 on farms if they are in close contact with livestock that is spreading the virus.
