How Foreign Matter Is Kept Out of a Can

Why This Is the Buyer's Problem

When a can carries a retailer's own brand, a foreign-matter complaint belongs to the retailer. The factory loses an order; the brand loses a listing and pays for the recall. That asymmetry is why technical teams spend more time on this than on price.

Raw Material Collection

Control starts before anything reaches the line. Raw material is inspected strictly at collection, because the cheapest place to remove a problem is before it has been washed, cut, filled and sealed inside a sterile container.

Metal Detection on the Line

All of the ingredients on the production line are checked by metal detectors. This catches fragments introduced during harvesting, transport and preparation, at a point where rejecting a batch costs a fraction of what rejecting finished goods would.

Sterilisation After Seaming

Once the can is seamed it is sterilised at high temperature so the product becomes commercially sterile. Sterilisation is what allows canned food to be stored and shipped at ambient temperature, and it is done after seaming so the sealed container itself is part of the barrier.

Double X-ray Scanning

Every tin and every glass jar is scanned by a double X-ray machine before packing. X-ray sees what a metal detector cannot: glass, stone, dense plastic and bone. Scanning after the container is closed also means what is being checked is the finished unit rather than a sample of the batch.

Independent Verification

The last step is not ours. Any inspection company a buyer designates is accepted to inspect the goods after production and before shipment, which is the point at which a problem can still be fixed cheaply.