What methodology did pre-serialized supply chain verification typically employ when attempting to trace a contaminated batch back to its origin?

Using existing batch records, shipping manifests, and invoices

Before the widespread adoption of modern, serialized track-and-trace systems, supply chain verification in the event of an issue, like product contamination, was largely reactive and manual. Companies were forced to rely on historical documentation maintained throughout the distribution process. This included checking physical or rudimentary digital batch records, invoices detailing transactions, and shipping manifests to slowly reconstruct the movement pathway of the affected product batch back to the point of origin for necessary recalls. This process was often slow, unreliable due to potential incomplete records, and highly prone to error.