"He went to go take a sip of the drink and he started choking," said Christina Stewart. "So he pulled the worm out of his mouth and he was like, 'Oh mommy, this is nasty.'"
Stewart said she called Kraft Foods, the parent company of Capri Sun.
"She was like, 'Well, I'll just give you your money back, like it wasn't a big deal," said Stewart.
She said she was also told someone would call her within 48 hours to learn more about her case.
Stewart took her son to the doctor, showed him the juice pack, and the slimy substance she was convinced was a worm. She said the doctor also thought it was a worm, and he sent it to a lab to be tested to know for sure.
Stewart's doctor did not discuss the case, citing patient privacy rules.
However, Stewart said she was told worms in humans can cause a variety of infections, and she is now monitoring her son's health for any warning signs.
A quick search online also reveals other customers who claim to have found a worm in their Capri Sun.
A spokesperson from Kraft Foods sent a statement, which reads in part:
"We're very sorry Ms. Stewart and her little boy had such an unpleasant experience. Of course, without seeing the material, we can only surmise, but we believe what she's identified as a worm may actually be mold. Since our Capri Sun products are made without preservatives -- a fact many moms like -- if there's even a small hole in a pouch and air gets into it, mold similar to common bread mold can form. This is why we advise on the side of the box to discard any leaking pouches.
“We do know that, among the many, many millions of pouches we sell each year, this has occasionally happened to others, and, when we've been able to examine the material, it has, in fact, turned out to be mold, not worms.
“With regard to Ms. Stewart's call to us, before our representative could ask her to send us the pouch in question, Ms. Stewart disconnected the call. However, we will ask one of our executive consumer representatives to call her."
Stewart is now waiting for the test results to come back to know for sure what the substance is. She said whether it was mold or worms, she has learned her lesson.
"Now, honestly, I'm going to buy drinks that I can see into to make sure there's nothing in them," she said.