What kid doesn't love Lunchables?

For decades, the prepackaged assortment of snacks – from deli meats and crackers, to pizza – have become a childhood staple for generation after generation. Lunchables have also in recent years become a menu item at many schools across the United States, thanks to the U.S. Department of Agriculture.

But Consumer Reports is hoping that changes.

Turns out, the popular snack may not be the healthiest option for growing kids. Lunchables contain a troubling high level of lead and sodium, the consumer watchdog group warned Tuesday in a new report.

“We don’t think anybody should regularly eat these products, and they definitely shouldn’t be considered a healthy school lunch,” Eric Boring, a chemist at Consumer Reports who lead the testing, said in a statement.

Lead concerns for kids:Recalled cinnamon applesauce pouches were never tested for lead, FDA reports

Consumer Reports finds high levels of lead, sodium in Lunchables

The advocacy group said it tested 12 store-bought Lunchables products, made by Kraft Heinz and compared them to similar lunch and snack kits from other manufacturers.

Although none of the kits exceeded any legal or regulatory limit, the tests uncovered “relatively high levels of lead, cadmium and sodium” in the Lunchables kits, said Brian Ronholm, director of food policy at Consumer Reports.

Classified as a human carcinogen, cadmium has been linked to kidney and bone disease, as well as cancer, according to the World Health Organization.  However, because cadmium is a natural element present in the soil, it can't be altogether avoided.

As for lead, no safe level exists for children to consume, the Centers for Disease Control and Prevention notes.

“There’s a lot to be concerned about in these kits,” Amy Keating, a registered dietitian at Consumer Reports, said in a statement. “They’re highly processed, and regularly eating processed meat, a main ingredient in many of these products, has been linked to increased risk of some cancers.”

The sodium levels in the store-bought kits ranged from 460 to 740 milligrams per serving, "nearly a quarter to half of a child’s daily recommended limit for sodium," Consumer Reports' testing found.

All but one of the kits, Lunchables Extra Cheesy Pizza, contained harmful phthalates – dubbed “everywhere chemicals” for their prevalence in plastic that can be linked to reproductive issues, diabetes and some cancers.

School lunch policies

Consumer Reports also analyzed two Lunchables kits made specifically for schools that are eligible to be served to children under the National School Lunch Program.

While the group didn’t test the school kits for heavy metals or phthalates, chemists did review nutritional information and ingredients lists in the two products – Turkey & Cheddar Cracker Stackers and Extra Cheesy Pizza – to find higher levels of sodium than store-bought versions.

To meet the requirements of the federally assisted school meal program overseen by the USDA, Kraft Heinz added more whole grains to the crackers and more protein to the school Lunchable kits, Consumer Reports said.

“Lunchables are not a healthy option for kids and shouldn’t be allowed on the menu as part of the National School Lunch Program,” Ronholm said in a statement.

Kraft Heinz told USA TODAY in a statement Wednesday the company has taken steps to make Lunchables more nutritious by, for instance, adding fresh fruits to certain kits and reducing the overall sodium by as much as 26%.

"Many of our Lunchables products are a good source of protein, offering nutrients through meats and cheeses," according to the statement. "All our foods meet strict safety standards that we happily feed to our own families ... We are proud of Lunchables and stand by the quality and integrity that goes into making them. 

CR petitions USDA to remove Lunchables from school lunch menus

As a result of its findings, the non-profit consumer group said it has petitioned the USDA to remove Lunchables from school cafeterias.

The petition had more than 14,100 signatures as of Wednesday morning.

A USDA spokesperson said in a Wednesday statement to USA TODAY that the agency "takes very seriously our responsibility to ensure school meals are of the highest nutritional quality.”

While the USDA doesn't specifically allow or prohibit individual food items, the agency has requirements in place to "address the overall content of meals," whether on a daily or weekly basis, the statement read. That means, Lunchables would need to be paired with fruit, vegetables and milk, and schools would have to balance how often they serve high-sodium meals, the agency said.

"This is why we have a new proposed rule which aims to align our programs with the latest nutrition science and modernize our services to best serve kids," the statement read. "Strengthening the nutrition of school meals comes from a common goal we all share: to help kids be healthy."

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at [email protected]