about the safety system that was meant to protect the whole batch.
test piece
source: Test Pieces
What to Do If You Find a Test Piece (or Anything Odd) in Food
Don’t just bin it and move on. A few practical steps go a long way:
Keep the disc and the packaging together. Don’t wash or damage the object.
Photograph the disc, then flip the bag and photograph the batch or lot code and the best-before date.
Contact the manufacturer directly with those photos and details. The batch code tells them where and when it was made.
In many countries you can also report a food safety concern to the relevant agency, which helps flag a systemic issue.
The best-supported answer is that your blue disc is a certified metal-detector test piece that escaped a factory’s quality checks. The useful move is documenting it and telling the maker, not guessing.
