Federal health officials are expanding an investigation into potentially lead-tainted pouches of apple cinnamon fruit puree marketed for children amid reports of more illnesses and additional product recalls.

The US Food and Drug Administration said on Friday it has received reports of seven illnesses in at least five states possibly linked to contaminated puree.

Two new companies, Schnucks Markets of St Louis and Weis Markets of Sunbury, Pennsylvania, announced recalls of certain cinnamon applesauce products because they may contain high levels of lead. WanaBana of Coral Gables, Florida, previously recalled all lots and expiry dates of its apple cinnamon fruit puree.

Eating the contaminated products could result in “acute toxicity”, FDA officials said. Parents and caregivers should not buy or serve the cinnamon applesauce products, which are sold through multiple retailers including Amazon, Dollar Tree and at Schnucks and Eatwell Markets grocery stores.

Children and others who have consumed the products should be tested for possible lead poisoning, the agency said.

The investigation began in North Carolina, where health officials are looking into reports of four children with elevated blood levels linked to the WanaBana product. State health officials analysed multiple lots of the product and detected “extremely high” concentrations of lead. The FDA confirmed the results.

The FDA’s Coordinated Outbreak Response and Evaluation Network is leading the investigation in co-operation with the US Centers for Disease Control and Prevention and state and local health officials.

Lead is toxic to people of all ages, but can be especially harmful to children. Most children have no obvious symptoms, so it’s important that kids who are exposed get tested to check levels of lead in their blood. Short-term exposure to lead can result in symptoms that include headache, abdominal pain, vomiting and anaemia, the FDA said.

Heavy metals like lead can get into food products from soil, air, water or industrial processes, according to the American Academy of Pediatrics (AAP). Lead exposure can seriously harm children’s health, causing damage to the brain and nervous system and slowed growth and development. There is no known safe level of lead exposure, the AAP said.