What is traceability? Batch level vs item level

Traceability is the ability to trace the history, application or location of an object. That is the definition GS1's Global Traceability Standard opens with, taken from ISO's quality management standard, ISO 9001:2015. For a product, GS1 adds, traceability can relate to three things: the origin of its materials and parts, its processing history, and its distribution and location after delivery.¹

Law uses a closely related definition. The EU's General Food Law defines traceability as the ability to trace and follow a food through all stages of production, processing and distribution. Its definition of food includes drink, so wine and spirits are covered.²

Both definitions have two directions built in. Tracing looks back: where did this come from, and what went into it? Following, or tracking, looks forward: where did it go, and where is it now? Product tracing in practice means being able to answer both for the products a business makes, moves or sells.^2,1

No single company sees a whole supply chain, so traceability is built link by link. GS1's standard sets a minimum for every member of the chain: be able to trace back to your direct suppliers, and track forward to your direct recipients, in some cases including end consumers. GS1 calls this one up, one down. Each pair of trading partners keeps its own records, and a question further up or down the chain travels one step at a time.¹

What gets recorded is a set of critical tracking events, the moments when something happens to a product, such as receiving, transforming, packing and shipping. Each event is described by key data elements covering who, what, when, where and why.¹

The hard part is that the routes are not known in advance. GS1 calls these emergent supply chains: units made and shipped together often end up in different places, and the brand that made them typically does not know the route each one took. Upstream, a company often does not know its suppliers' suppliers.¹

Manufacturing traceability connects finished products to what went into them. GS1's scope covers the transformation of raw materials, ingredients and components into products, and the aggregation of products for transport. Its worked example is canned tuna: the tuna loin, the olive oil and the cans are the primary materials, and the cartons the cans are packed into are secondary.¹

A factory rarely uses one identification level throughout. GS1 notes that companies often combine levels, especially where inputs are transformed into new products, and that products and ingredients associated with high risks will always be identified at batch or instance level.¹

How far you can trace depends on how finely each product is identified. GS1 describes three levels. At class level, every unit of a product carries the same trade item number, so a system can tell one product from another but not two units of the same product. At batch or lot level, the number is extended with a batch number, so units from different batches can be told apart, but not two units within the same batch. At instance level, each unit carries its own serial number, so the trade item number and the serial number together identify one item and no other.¹

Each step down that list gives more ability to trace, at the cost of more bookkeeping and more expensive marking. Class-level marking is usually the cheapest, because it can be printed into packaging artwork in bulk.¹

Item level changes what a record can show. A serialized object can only be in one place at a time, so its events trace a single, unambiguous path through the supply chain. A batch record says where the batch went; an item record says where this item went, and only this one.¹

With item-level identification, tracing starts from the object itself. Its identifier is read from the label or tag on the product. That identifier finds the events recorded about it, each with its who, what, when, where and why. From those events, tracing goes back to the supplier and the batches that went into it, and forward to everyone who received it after.¹

In EU food law, traceability has been a general obligation since 1 January 2005, the date from which Article 18 of the General Food Law applies. It must be established at all stages of production, processing and distribution. Every food and feed business must be able to identify who supplied it, and must have systems to identify the businesses it supplied. That information must be available to the authorities on demand, and products must be labeled or identified to make tracing possible. It is one step back and one step forward, written into law.²

The EU's Ecodesign for Sustainable Products Regulation (ESPR) makes traceability one of the stated aims of the Digital Product Passport: its requirements must improve the traceability of products along the value chain. The regulation calls unique identification of products a fundamental element of traceability. It leaves the level to each product group's delegated act, which decides whether the passport is kept at model, batch or item level. In the regulation's own terms, a batch is usually the products made in one plant at one time, and an item is a single unit.³

US prescription drug law goes to the unit. Under the Drug Supply Chain Security Act, the September 2023 guidance from the US Food and Drug Administration (FDA) describes requirements going into effect on November 27, 2023: tracing information exchanged electronically between trading partners, generally including a product identifier for each package, verification at the package level, and a prompt response when officials ask for it in a recall or an investigation.⁴

The last point matters more as products are resold. A batch record ends at the sale, when the batch scatters. An item record can keep going.

• At what level is each product identified: class, batch or item? And is that the level your regulator or your customers will ask for?
• Can you trace one step back and track one step forward, for every product, on demand?
• Which critical tracking events do you record, and does each one say who, what, when, where and why?
• Where does the identifier live? A number on a carton is lost when the carton is thrown away; one on the product stays with it.
• Does the record stop at the first sale, or can it follow the product to later owners?
• Can anyone holding the product check it, or only your own staff?

Vera works at item level. A Vera Tag gives one item its identity. For most brands it goes in at manufacture: inside a watch behind the dial, or in a garment's label. Tags can be bound to their products before a box leaves the factory, so the record starts at the source.

From there, each handover is a tap on the same tag, and each tap lands on that item's own certificate as it happens: factory, warehouse, store, first owner, second owner. Every scan, transfer and resale is written to that one certificate, so the record outlives every owner. A brand can send an item to one of its own locations, which confirms arrival with a tap, and anyone holding the item can check it at a handover with a phone and no app. A Verify + Trace tag reads with a phone tap and with warehouse and retail radio-frequency identification (RFID) readers. A product made of separately sold parts is handled as one parent certificate with a child for each part.

Vera provides the item-level identity and lifecycle record a Digital Product Passport is built on: the tag on the product, and a record of every transfer, scan and resale.