cGMP (current good manufacturing practice)
The FDA's manufacturing-quality rules for dietary supplements (21 CFR Part 111), which cover how a facility controls ingredients, equipment, testing and records. A recall that cites cGMP deviations is about the process that made a product rather than a single contaminant found in it.
Example
FDA enforcement records often cite cGMP in the reason for a recall, for example "CGMP Deviations: Intermittent exposure to temperature excursion during storage."