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 deviations" as the reason when an inspection finds the facility could not show a product's identity, purity or composition.