Some veggie puffs made by Lesser Evil and Serenity Kids contain concerning levels of lead, a heavy metal linked to developmental and other disabilities in children, according to findings released Wednesday by Consumer Reports.

Parents may see veggie puffs, marketed as a healthy alternative to sugar-laden snacks, as a way to make foods like beets, carrots, potatoes and tomatoes palatable for kids. But certain cassava-based brands have excessive amounts of lead or other heavy metals, making even a single serving unhealthy in the case of one product, the advocacy group cautioned.

Troublesome levels of lead were found in both Lesser Evil puff products tested and one from Serenity Kids, Consumer Reports found. Lesser Evil's Lil' Puffs Intergalactic Voyager Veggie Blend puffs had more lead per serving than any of the 80 baby foods the watchdog has tested since 2017, the group noted.

"We think kids should consume less than half a serving a day of those," James E. Rogers, head of food safety testing at Consumer Reports, said in a statement. 

As for the other two puff products that showed high lead levels — Lesser Evil's Lil' Puffs Sweet Potato Apple Asteroid and Serenity Kids' Tomato & Herb Bone Broth puffs — Consumer Reports advises limiting consumption to 1.5 servings a day. 

Puffs and other snacks made with rice can be high in arsenic, prior tests by Consumer Reports found. That prompted some manufacturers to use other starches, such as the root cassava or sorghum, a gluten-free grain.  

Consumer Reports found very low levels of lead in two sorghum-based products from Once Upon a Farm, a company co-founded by actress Jennifer Garner. The company's snacks also yielded some of the lowest lead levels of all the baby foods tested by Consumer Reports, it noted. 

"Clearly, some manufacturers need to do a better job of keeping heavy metals out of their snack foods, and there may be some particular concerns about foods made with cassava," Rogers said.

Macarena Rizzo, a mother of two who has given veggie puffs to her 15-month-old daughter, expressed concern about the findings. 

"Very, like, disappointed because I thought that I was making a good choice or like a smart choice, and seems like it's not," she told CBS News senior consumer investigative correspondent Anna Werner.

Parents who have given their children cassava puffs shouldn't panic, but instead be cognizant that the amounts found by Consumer Reports could over time raise the risk of developmental problems, such as lower IQ, ADHD and autism. 

"You have to account for the fact that small amounts of lead can add up and that children may be exposed to some lead in drinking water or their environment," Rogers said. "That's why foods with more lead should be minimized in a child's diet."

Lesser Evil said that all of its products adhere to regulatory requirements. "Lesser Evil was built on a mission to create better, cleaner, more natural products than the highly processed and refined snacks that overtook grocery store shelves for years," the company told CBS MoneyWatch in a statement.

The company's products "all meet GRAS (Generally Recognized as Safe) standards and federal regulations for organic products," Lesser Evil stated, adding that "we conduct extensive testing for all Lesser Evil products that complies with California Prop 65 and federal standards."

Sami Rosnov, chief of operations at Corner Market Communications, which represents Lesser Evil, told Consumer Reports that lead occurs in nature "due to years of pollution and contamination in our water and soil."

Serenity Kids also defended the company's products, including its testing and quality assurance practices. 

"Our puffs are and have always been safe for consumption. All of our products test well below the Maximum Allowable Dose Levels (MADLs) established by California Proposition 65," the company said in a statement. 

"We have always addressed lead and all heavy metals head on because we are confident in the safety of our products and ingredients, and because we believe that our products are healthier than the alternatives that exist today," the company added.

In a statement, Once Upon a Farm also noted that heavy metals occur naturally in the environment, making them "virtually impossible" to avoid. "Our standard is to minimize their presence to consumable levels in all our products," the company told CBS MoneyWatch. 

Once Upon a Farm said it also seeks to reduce heavy metals in its products by using organic ingredients from global regions that have taken steps to lower risks and by testing the materials most likely to contain metals. Emily Luna, baby brand manager at Once Upon a Farm, also said the company chose sorghum for its puffs in part because it's less likely to contain heavy metals than rice or cassava. 

The findings follow the release of separate results in April in which Consumer Reports found that Lunchables, another popular food product for kids, contains troublesome levels of lead and sodium. 

"The classification of foods should be based on scientific evidence that includes an assessment of the nutritional value of the whole product, not restricted to one element such as a single ingredient or the level of processing," a spokesperson for Kraft Heinz said in defending the 35-year-old brand.

A government report in 2021 found that baby food made by several of the nation's biggest manufacturers had "significant levels" of substances including lead, arsenic, cadmium and mercury, prompting the FDA to propose limits on arsenic, lead and mercury in baby food. 

Kate Gibson

Kate Gibson is a reporter for CBS MoneyWatch in New York, where she covers business and consumer finance.