A shelf-life safety margin is not a fixed percentage. It should be justified by product validation, batch variability, measurement uncertainty and distribution conditions.
Before testing, define product and pack, represented production batches, storage conditions, measurement method and acceptance criteria. Make traceable which data supports the date decision.
Establish actual chain conditions from route and storage records. Assess whether the laboratory study covers them and separately review assumptions such as transfers, retail and consumer storage.
Record data distribution, uncertainty, rationale for the margin and approving owner in the report. Do not derive a use-by date from a generic formula or one sample.
Assess impact when ingredients, formulation, process, packaging or distribution conditions change. The product-safety owner should decide whether further study is needed.
