Nestle has some of the most severe, stringent, and onerous procedures for correcting glass contamination that I know of. When Nestle tells their employees glass production is over, dismantles equipment to the bone yard, and then gives the old tallyho we’re bringing it back—dark thoughts ensue.
Glass jewelry, Gorilla glass, and common plant area lab instruments.
Watches are allowed in possession but not to be worn. Typical magnets will not seize metal/glass jewelry very well, if it is ground up.
Glass can cling to shoes.
Any ingredient transported into a plant can contain contaminants.
Do workers go through a cleanroom?
A few years back a similar recall occurred at unrelated company. After months of analysis, it was discovered incident was traced to a bin of ingredients backed into a wall mounted fire extinguisher in area outside a cooler. The gauge was broken. Case study at auditor certification in root cause analysis