Keeping manufactured product within specification by testing representative samples. Food-plant QC labs pull raw materials, in-process streams, and finished goods, measuring composition, microbial safety, sensory quality, and package integrity against written standards, then accept or reject each lot. Unlike quality assurance, which designs the system, quality control verifies its output, and the two work as a pair. Statistical sampling plans, calibrated instruments, and trained analysts decide whether a day’s production ships or is held for investigation. Trend analysis of QC data provides early warning of process drift.