A Westport seventh-grader found an unwelcome surprise in his chocolate chip muffin -- a 1 inch steel bolt baked into the treat.

Superintendent Colleen Palmer emailed Coleytown Middle School parents to say the student found it before taking a bite. The school halted muffin sales immediately and inspected the rest of the batch. No other foreign objects were found.

Officials contacted the bakery that made the muffin, and an investigation is underway. 

"They have a theory that a screw came out during the batter portion of the baking cycle, and we will not be having muffins from this vendor until we make sure that their safety controls are back in place and everything is fine," Palmer says.

The vendor thinks the bolt came out while the muffin batter was in a mixer.