A Canberra woman found a three-centimetre bolt in a muesli bar.

Christine Pobke said she had noticed something out of the corner of her eye as she unwrapped the muesli bar on Tuesday.

Ms Pobke, from Belconnen, said she emailed the bar’s manufacturer and included photos, but was not satisfied with the response.

"Throwing a whole lot of acronyms at me about their accreditation doesn’t make me confident about buying more of their products.”