Mothers who catch their baby eating food off the ground may have no cause to worry, provided their young one isn’t eating an actual mud pie.

Numerous researchers told the New York Times that things such as worms and dirt can assist the development of the immune system.

Dr Joel V Weinstock, director of gastroenterology and hepatology at Tufts Medical Center in Boston, said a baby’s immune system was "like an unprogrammed computer. It needs instruction," the Times reports.

"Children raised in an ultraclean environment are not being exposed to organisms that help them develop appropriate immune regulatory circuits," Weinstock told the news provider.

The doctor, along with his colleague Dr David Elliot, has found intestinal worms were a huge factor in regulating the immune system, according to the article. They have also conducted studies using such worms to prevent and reverse autoimmune disease.

"Children should be allowed to go barefoot in the dirt, play in the dirt, and not have to wash their hands when they come in to eat," Weinstock said.

However, the researchers in the article are quick to say this does not mean children should be rolling around in filth either.