Forward vs. backward lot traceability, explained
Understand the two questions every connected lot history must answer during an investigation or recall.
Backward traceability asks where it came from
Starting with a finished lot, backward tracing identifies its production batch, every ingredient or component lot consumed, and the suppliers behind those lots. This is the path used to investigate a customer complaint or quality failure.
Forward traceability asks where it went
Starting with a supplier lot, forward tracing identifies every batch that consumed it, all resulting finished lots, remaining inventory, and customer shipments. This is the path used to define recall scope.
You need both directions
A list of purchase receipts cannot identify affected customers. A shipment list cannot explain which supplier lots were used. The value comes from preserving the connections between receiving, production, packaging, inventory, and shipping.
Test both directions regularly. A trace is complete only when the team can move from source to sale and sale back to source without rebuilding the history by hand.