The Food and Drug Administration has begun screening incoming shipments of cinnamon from multiple countries, the agency announced this week, as reported illnesses have climbed to 34 in the investigation of lead poisonings linked to pouches of cinnamon-flavored applesauce.

The FDA has ramped up its investigation in recent weeks, after authorities in North Carolina first warned of the possible link to applesauce when investigating cases of lead poisonings in the state. Cases across at least 22 states have now been linked to the pouches, which were sold nationwide under the now-recalled brands of WanaBana, Weis and Schnucks.

The Centers for Disease Control and Prevention warned testing laboratories nationwide this week to brace for a potential influx of lead testing requests, as cases reported linked to recalled applesauce pouches have swelled.

The FDA said its “leading hypothesis” now blames the toxic lead levels on cinnamon used to produce the applesauce. Other fruit puree products made by the recalled brands did not have high levels of lead and have not been recalled.

Samples collected from a WanaBana Apple Cinnamon Puree product from Dollar Tree tested positive for lead levels “more than 200 times greater” than proposed limits the FDA has set for products intended for babies and young children, the agency said.

On-site inspections are now ongoing, according to an FDA table, alongside efforts to trace back the ingredients behind the poisonings.

Schnuck Markets had also previously blamed “cinnamon raw material” supplied by Ecuador-based Austrofood, the parent company of WanaBana, for the recall. 

However, the FDA said it has yet to secure samples of the cinnamon used in the recalled products to test and is still working with authorities in Ecuador to track down the source.

While the agency has not received reports of other cinnamon products causing lead poisonings, the FDA said it would begin screening imports of cinnamon “to further protect public health.”

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“This is a very high priority for us and we are investigating aggressively. I hope we have our arms around this,” Jim Jones, the FDA’s deputy commissioner for human foods, said Monday at an event by the Alliance for a Stronger FDA.

Jones acknowledged that it was possible other foods on the market may have used the lead-contaminated ingredients.

“Our ability to be 100% confident around exactly where it is, that’s just a lot of leg work and investigative work and partnering, and we’re trying to do all those things, and hoping we can get this thing wrapped up quickly, meaning out of the food supply,” said Jones.

It is unclear what additional countries FDA is screening cinnamon shipments from. An FDA spokesperson did not immediately respond to a request for comment.

Children ages 1 to 3 years old tested had blood lead levels as high as 29 micrograms per deciliter after consuming the applesauce, according to a CDC alert Monday

At those levels, the CDC says doctors should contact specialists or poison control centers and arrange for investigations to address the issue.

Symptoms reported by children included headache, nausea, vomiting, diarrhea and change in activity level.

“Although children with lead exposure may have no apparent acute symptoms, even low levels of lead have been associated with learning, behavioral, and cognitive deficits,” the CDC warned in its alert, urging parents who purchased the recalled pouches to get their children tested for lead poisoning.