(KMGH/CNN) -- A Colorado family says they'll never forget to check the expiration date again after eating cereal they believe to be decades-old.
Josiah Carelse said he purchased a box of Quaker 100% Natural Granola cereal from a Walmart store in Littleton on Monday
It wasn't until he and his family sat down and ate a serving that they realized something was wrong.
"I just started eating and thinking it tastes funny," he said.
His wife, Anthea, said she checked the box and noticed the printed "best by" date said Feb. 22, 1997.
Anthea said she only had two bites before noticing the date, but her husband ate a full bowl.
"I was like, Josiah, 'You're gonna be really sick," she said.
Fortunately, he's feeling fine and plans to return the expired box to Walmart.
The family went online to compare what a current Quaker cereal box would look like. The new look is much different than the box they purchased.
KMGH-TV confirmed the item's UPC number printed on the family's Walmart receipt matched the code printed on the cereal's label.
A Walmart spokesperson says the company is looking into the matter.
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