Agriculture & Future Food Systems · Article

Lots, identifiers and chain-of-custody records

Follow identified food through receiving, mixing and dispatch without confusing a readable code with a verified physical history.

Preparation and related reading

Shared Foundations

This article helps you

Explain how identifiers connect physical food and movement records.
Retain input links when food is mixed, split or transferred.
Check a specified traceability boundary and distinguish quantity closure from safety.

Start with one mixed lot

Imagine a processor receiving two dry-lentil lots from different identified suppliers. The lentils are combined into a new lot and sent to two kitchens. If one input later needs investigation, the useful question is which combined lot and destinations received it.

Traceability is the ability to follow food through specified stages. A lot identifier provides a handle for those records. The chosen lot should have a clear meaning within the actual operation; a name printed on several bags does not itself establish when, where or from what their contents were made.

Link physical food to records

At a transfer, connect the product and lot identity with the sender, receiver, quantity and relevant dates. A custody record describes who held or transferred the specified food. Physical identification and records need to stay connected when packaging or responsibility changes.

An identifier must be interpreted in its context. Two suppliers could use the same short code for different products, so keeping the supplier and product relationship matters. A receipt may also differ from a dispatch declaration. Record the actual observation and unresolved difference rather than copying the expected number as a measured fact.

Preserve mixing and splitting links

In the diagram, input A contributes 20 kg and input B contributes 30 kg to new lot C. All 50 kg are mixed and later split into 30 kg for kitchen X and 20 kg for kitchen Y. Assume no other inputs, outputs, storage change or mass transformation.

The new identifier C should link back to both inputs and forward to both destinations. It cannot replace those links. For this hypothetical full mixture, both destinations are connected to both contributing lots. That statement concerns the recorded mixing arrangement, not a laboratory finding about the distribution of a contaminant.

Preserve both sides of a mixing event

Record relationships, not contaminant concentration, mixing validation or safety certification; nodes and arrows have no physical scale.

Read the diagram as text

Original hypothetical complete mixing of 20 kg A and 30 kg B into 50 kg C, then splitting 30 kg to X and 20 kg to Y. All quantities share one unchanged food-state basis with no other flows.

Parts

Input A: 20 kg: Keep supplier, product and lot context
Input B: 30 kg: Second contributing lot retains its identity
Mixed C: 50 kg: Links both inputs to both recorded destinations
Kitchen X: 30 kg: Receipt linked to C and its input histories
Kitchen Y: 20 kg: Receipt linked to C and its input histories

Connections

Input A: 20 kg → Mixed C: 50 kg: input link
Input B: 30 kg → Mixed C: 50 kg: input link
Mixed C: 50 kg → Kitchen X: 30 kg: dispatch link
Mixed C: 50 kg → Kitchen Y: 20 kg: dispatch link

Define what the system can follow

A receiver’s records can identify the immediate sender, but following a longer journey requires reliable linked records at the preceding stages. Specify whether the task covers supplier receipt, internal processing, dispatch or a wider chain. A missing stage leaves a gap in the answer.

Internal links are especially useful when ingredients become another product or one lot becomes many shipments. Include the relevant transformation rather than showing an unbroken line that never happened. The neighbouring mixed-product topic explains product composition; here the focus is preserving its history.

Test the records with a question

Take a selected destination lot and work backwards through the saved links. Then choose an input and follow its recorded destinations. Check the actual documents and physical identifiers rather than only asking whether a software screen can display a diagram.

The two directions answer different questions. A quantity account can help reveal an omitted shipment or unexplained transformation, but arithmetic closure does not establish truthful entries, authenticity or food safety. A copied incorrect quantity can make an internally tidy system that misdescribes the food.

Keep record quality visible

Retain the basis for an entry and identify corrections clearly. If a receipt is missing or a source code cannot be interpreted, mark the link unresolved and investigate it. Do not invent a supplier history simply to complete a form.

Traceability supports targeted investigation and response when combined with appropriate action. It does not prevent every hazard or certify that a product is suitable. Design a practical record system for the actual food, operations and purpose; the incident-response topics explain how the information can be used when a problem arises.

Worked examples

Follow the stipulated mixture

A 20 kg and B 30 kg become C 50 kg. C sends 30 kg to X and 20 kg to Y with no other flows. Which input and destination links belong to C?

Input total = 20+30 = 50 kg.
Dispatch total = 30+20 = 50 kg.
Retain A→C and B→C; retain C→X and C→Y.

C links to both inputs and both destinations. Under the stated complete mixing, both destinations received material from both inputs; no safety conclusion follows.

Find an unresolved quantity

For a separate unchanged food-state account, records show 100 kg received, 70 kg dispatched and 20 kg still held, with no other stated movements. What remains unexplained?

Accounted amount = 70+20 = 90 kg.
Difference = 100−90 = 10 kg.
The records alone do not identify its cause.

10 kg remain unexplained. Investigate the actual boundary and records; do not automatically label it theft, waste or harmless drying.

Check your understanding

Do identical short codes from two suppliers necessarily identify one physical lot?
Show answer and reasoning
No.
The supplier, product and lot context may differ.
Can the new code C erase the contributing lot histories?
Show answer and reasoning
No.
Mixing creates a new recorded relationship, not a substitute for input links.
Does a perfectly closed stock account prove the food is safe?
Show answer and reasoning
No.
Quantity consistency does not establish safety or truth of all entries.

Key ideas

Connect lot codes with actual product, custody and movement records.
Keep the input and output links across mixing and splitting.
Test the specified scope and retain unresolved evidence gaps.

References

Sources supporting the explanations and examples in this article.