How should slice-thickness accuracy be written into a purchase contract?

Slice-thickness accuracy belongs to a defined product and setup, not to the machine alone. State the material, its temperature, target thickness, gauge, and sample size—say, semi-frozen pork belly at -5°C, 4 mm, 20 slices measured by caliper, with mean deviation within ±0.3 mm and no single slice beyond ±0.8 mm. Different fat content or hardness needs its own specification. During the factory test, run the same batch for 30 minutes, log mean and worst deviation, and record feed rate, blade speed, and tension. Accept the line only when two consecutive production batches hold the slice profile; after any changeover, re-qualify the first article.