Lot and serial traceability guide

Traceability is the ability to follow the history, location and use of a product and the materials it is made of through records. In practice it means answering two questions quickly and reliably: Which materials was this product made from, and under what conditions? Which products did this material go into, and who received them? This guide brings together the decisions, templates and checklists that manufacturers and distributors need when they design and roll out a traceability system.

Forward and backward traceability

Backward traceability starts from a finished product and moves back to its components, raw material lots and suppliers. You use it to find the root cause of a customer complaint. Forward traceability starts from a raw material lot and moves forward to the products it was used in and the customers those products were shipped to. You use it to find affected products and customers when a supplier reports a defect.

A good system answers both directions from the same data. Companies that build only one direction usually build backward tracing, yet forward tracing is the capability that narrows a recall. The more precisely you can draw the scope, the more closely the recalled quantity matches the real risk.

Lot, serial or batch: which should you choose?

The unit of traceability (granularity) sets the precision and cost of the questions the system can answer. A lot is a group of products made under the same conditions and treated as identical. A batch, especially in process and chemical industries, refers to a single production run or recipe execution, and most systems use it as a synonym for lot. A serial number uniquely identifies a single unit of product.

Many companies use a mixed model: raw materials are tracked by lot, and critical subassemblies and finished goods by serial number. Choose lot size deliberately, too. Lots bounded by a shift, a raw material lot or a line cleaning give a narrower scope at recall time.

Define the events you trace

Traceability is built by recording specific events in the product's physical journey. For each event, define in advance which data is recorded, by whom and with what tool. A single missing event creates a break in the genealogy.

Data model: parent-child genealogy

The heart of traceability data is the genealogy. At every production event, the consumed lots are linked as “children” and the new lot or serial as the “parent”. These links accumulate into a tree that runs from a finished good down to the lowest raw material. Read the same tree in reverse and you get forward tracing.

• Unique identity: every lot and serial needs an identifier that never repeats across the system. The supplier lot is mapped to the internal lot but does not replace it.
• Link table: contains the parent ID, child ID, consumed quantity, work order and timestamp.
• Status field: statuses such as released, quarantined, rejected and shipped, with a record of every change.
• Context data: line, equipment, operator role, recipe version and key process parameters, used in root cause analysis.
• Immutability: records are never deleted afterwards; corrections are made with a reversing entry and a reason.

Labelling, barcodes and scanning points

GS1 standards let products and logistic units be identified in a common language across the supply chain. In the GS1 system, data is tagged with application identifiers (AIs): the number in parentheses says what the following data is. The parentheses appear only in the human-readable text; they are not encoded in the barcode.

• A GTIN is based on the company prefix you get through GS1 membership; do not make up your own numbers. A 13-digit GTIN is padded to 14 digits with a leading zero in the (01) field.
• The last digit of a GTIN and an SSCC is a check digit calculated with the GS1 algorithm.
• If another field follows a variable-length field, an FNC1 separator is used. Putting fixed-length fields first and variable-length fields last keeps the label simpler.
• GS1-128 is the linear barcode commonly used on case and pallet labels. GS1 DataMatrix is a two-dimensional code that carries a lot of data in a small area and is common in healthcare.
• Validate the label template against customer and industry requirements; some customers apply their own rules for field order, size and position.

Scanning points and hardware

A scanning point is where one of the events above takes place. At each point, choose hardware that suits the environment and does not slow down the operator. Scanning should be a natural step in the workflow; when it is seen as a separate “data entry job”, it gets skipped.

• Handheld terminal: for receiving, warehouse and shipping; industrial grade, resistant to drops and dust.
• Fixed scanner or camera: on the line, for automatic reading while the product moves.
• Label printer: for production output and case labels, with durable thermal transfer printing.
• Barcode verifier: to check the print quality of printed barcodes.
• RFID: for crate and pallet applications that need bulk reading without line of sight.
• Offline operation: buffering on the terminal so scans are not lost during network outages.

Handle exceptions: split, merge, rework, returns

Traceability systems usually break not in the standard flow but in exceptions. Write the rule for each exception type in advance and define it as a separate transaction in the system.

• Lot split: when a lot is divided into several containers or locations, the sublots must stay linked to the parent lot. A sublot inherits the full history of the parent lot.
• Lot merge: when different lots mix in a tank or silo, a new lot is created and all source lots are linked to it as children. Merging widens scope; manage the recall risk knowingly.
• Rework: reworked product keeps its identity or gets a new one; in both cases the rework event, any additional materials and the quality decision are recorded.
• Scrap and waste: quantity consumed but not turned into product is recorded; otherwise the quantity balance does not add up.
• Customer return: a returned product is received under its original lot or serial identity, and the decision to restock, rework or scrap is recorded.
• Unreadable identity: a rule for verifying identity and relabelling product with damaged labels is defined; matching by guesswork is not allowed.

Recall simulation drill

A recall drill (mock recall) tests the traceability system before a real event. The drill measures not whether data exists, but whether it can be found accurately and completely under pressure. Repeat drills across different product groups, in both forward and backward directions, and without advance notice.

1. 01
   Choose the scenario

   Pick a realistic trigger: a supplier defect in a raw material lot or a customer complaint about a finished good lot. Record the starting lot and the drill start time.

2. 02
   Build the scope

   Trace forward and backward from the starting lot: affected semi-finished and finished lots, quantities in stock and shipped, customers and delivery notes.

3. 03
   Balance quantities

   For each affected lot, compare the incoming quantity with what was consumed, remains in stock, was shipped and was scrapped. An unexplained difference signals a data gap.

4. 04
   Verify physically

   Check that the quantity the system shows in stock is really in the warehouse and in the right location.

5. 05
   Rehearse communication

   Confirm that customer and supplier contact details are current and that the decision makers and their order are clear. Before you contact a real customer, state clearly that it is a drill.

6. 06
   Evaluate and improve

   Report the time taken, missing records and breaks in the chain. Open a corrective action with an owner and due date for every gap found.

Regulatory and industry context

Traceability is a legal or contractual obligation in many industries, but its scope and level of detail vary by industry and market. The summary below is general guidance only. Confirm the obligations that apply to you with a regulatory expert in your industry or your legal team.

• Food and feed: in the European Union, Regulation (EC) No 178/2002 requires businesses to identify at least the previous and next link in the chain. Food legislation in Türkiye also defines traceability obligations. Food safety standards (for example ISO 22000 and GFSI-recognised schemes) expect traceability and recall drills.
• Pharmaceuticals: many countries require a unique serial number and a two-dimensional code on medicine packs; in Türkiye the Pharmaceutical Track and Trace System (İTS) serves this purpose. Requirements differ by country.
• Medical devices: markets such as the European Union and the United States have unique device identification (UDI) requirements.
• Automotive: IATF 16949 addresses product identification and traceability (clause 8.5.2.1) with a risk-based approach; customer-specific requirements may ask for more detail.

KPIs and rollout plan

A traceability system's success is measured by how quickly and completely it can answer during an event. Define the indicators below before rollout and set their targets according to your own risk and customer requirements.

Start the rollout with a single line or product group, and widen the scope after the first drill. OREL TTS keeps lot, serial and genealogy records from receiving to shipment; used together with OREL MRP, work order and consumption data come together in the same flow.

Common mistakes

• Backflushing production consumption from the recipe without scanning the actual lot.
• Not recording the supplier lot at receiving, so backward tracing stops at the supplier.
• Defining lots larger than needed, so the recall scope grows unnecessarily.
• Not defining merge rules at silos, tanks and blending points.
• Making up GTINs, or not validating label templates against GS1 and customer requirements.
• Designing scanning as a separate step that burdens the workflow.
• Handling exceptions outside the system, on paper or with manual fixes.
• Never running a recall drill, or always testing the same easy scenario.

Conclusion

Traceability is less a labelling or software project than the discipline of recording every event at the right moment with the right data. Choose the unit of traceability deliberately, define events and exceptions clearly, apply GS1 standards correctly and test the system with regular drills. Then, when a complaint or recall happens, you can draw the scope from evidence rather than estimates.