"I opened up and I asked my mom, is there supposed to be a ring in here?" Postol told CBS affiliate WSPA.
Her mother Stephanie looked inside the bag and noticed a small silver band with what looked like little diamonds in it.
A spokesperson for the company told ABC 4 Utah that they were "very surprised" to learn about this incident.
"We do take it very seriously and we have in place a number of processes to avoid something like this from happening," Anna Burr said. "And the other thing is all the packs pass through a very sensitive metal detector. So we really want to get the pack back so we can understand how this might have happened."
Pepperidge Farm does not allow employees to wear jewelry on the job and requires them to wear gloves while working.
The Postols are planning to send the ring back to the company so that they can determine how it ended up where it did.
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