Batch Codes on Cosmetic Bottles: Lot Numbering, Expiry Dating and Recall Readiness

A batch code identifies the production run behind every bottle, and a buyer specifies it with four decisions: the number format, the placement, the marking method and the traceability record behind it. EU Regulation 1223/2009 requires a batch reference on cosmetic labelling, and a period-after-opening symbol for products with a shelf life over 30 months. The right marking method depends on the substrate, the line speed and how much handling the pack will survive.

Nobody buys a bottle for its batch code, and everybody needs one when something goes wrong. A missing or illegible code turns a targeted withdrawal of one production day into a withdrawal of every unit in the market, because there is no way to tell which units are affected. The number itself is simple; the discipline behind it is not. The code has to survive filling, cartoning, shipping and two years in a bathroom, and the record has to let anyone pull the resin lot, the machine and the operator from the number alone. This guide covers the format, the dating rules, the marking methods and the record that makes a recall possible.

Why Does a Batch Code Matter?

The code is the unit of a recall. When a filling line discovers a contamination issue on one day's production, the batch code is what separates the affected units from the 200,000 good ones sitting in the same warehouse. Without it, the brand recalls everything, pays for everything, and loses the listing that follows.

The code is also a regulatory requirement in the EU. Regulation 1223/2009 requires cosmetic labelling to carry a reference that identifies the batch, so a product without one is non-compliant on the shelf before any problem arises. Retailers and marketplaces increasingly check for it during onboarding, which means a missing code can block a launch rather than merely complicate a recall.

And it is the entry point into every quality conversation that follows. A complaint about a leaking pump is only actionable if the customer can read a code and the supplier can pull the record behind it. Our ISO 22716 guide explains the documented system that record sits inside.

How Should You Format a Lot Number?

A good code is short, human-readable and self-describing. The common pattern is a date plus a run identifier, for example 260901-2 for the second run on 1 September 2026, or a Julian form such as 26244 for the 244th day of 2026. The date-first form is easier for a customer service team to read aloud over the phone, which is where most codes are first recorded.

Keep the code separate from the artwork date. Artwork carries the period-after-opening symbol and any expiry date, and those are fixed for the life of the design. The batch code is variable data applied at production, so putting it in the printed artwork means reprinting plates every run instead of changing a setting on the coder.

Write the legend down and share it. Both sides must be able to decode YYMMDD versus DDMMYY, and the difference is the reason a traceability exercise sometimes fails. A one-page document naming the format, the character set and the reset rule prevents the ambiguity better than any amount of good intent. Our QR and NFC guide covers the digital alternative that carries far more than a date.

Expiry Date or Period After Opening?

The two are different statements. An expiry date is an absolute 'best before' and applies where the product has a shelf life of 30 months or less under EU rules. A period-after-opening symbol, the open jar icon with a number and the letter M, states how long the product stays safe once the consumer first opens it, and it applies where the shelf life exceeds 30 months.

Most skincare carries the open jar symbol, with 6M, 12M or 24M being common. The number is not a guess: it is supported by stability and preservation testing on the formula, so it is the brand's responsibility rather than the bottle supplier's. What the supplier controls is that the symbol is legible, durable and in the artwork at the right size.

Check the minimum symbol height and contrast in the target market before the artwork is finalised, because a symbol printed too small to read is a finding in an audit even when the number behind it is correct. Our label adhesive guide matters here, since a label that lifts in a wet bathroom takes the dating information with it.

Laser Coding vs Continuous Inkjet

Laser coding removes material or changes the surface layer of the plastic, so the mark becomes part of the bottle. It cannot rub off, it needs no consumable, and it holds up through filling, shipping and a wet bathroom. The trade-off is contrast: a laser mark reads best on dark or pigmented surfaces and can be faint on clear or very light bottles, and it will not mark every coating equally.

Continuous inkjet, or CIJ, throws charged ink droplets at the surface. It runs at high line speed, prints on almost any substrate including curved and coated surfaces, and gives strong contrast in a colour of the brand's choosing. The trade-off is durability, which depends entirely on ink-substrate matching, so a CIJ code needs an abrasion test and a solvent rub test before the run is approved.

Pick by the pack and the channel. Laser suits high-volume bottles on dark resin where permanence matters most. CIJ suits multi-SKU short runs, light-coloured bottles and anything needing a specific print colour. Either way, validate: rub the code with a solvent, run it through a realistic carton and pallet cycle, and re-check legibility at the end. Our screen printing durability guide sets out the same test logic applied to decoration.

What Goes Into a Batch Traceability Record?

The record must let anyone start from the code and work backwards. It names the production date and shift, the machine and the mould, the resin lot and masterbatch lot, the closure and pump lots, the operator, the in-process check results and the AQL inspection decision. ISO 22716 sets out the batch record discipline on the filling side, and a packaging supplier serious about traceability keeps the mirror of it.

It must also work forwards. Given a resin lot, the supplier should be able to list every batch code that used it, because a material problem is traced outward from the material, not inward from the code. Ask the supplier to demonstrate both directions during qualification, and time them; a well-run factory answers in minutes.

At ShiJin we run 1,000+ mold designs, MOQ 5,000 units and 15-25 day production. We apply batch codes by laser or CIJ depending on the resin and the run length, we check legibility against an abrasion and solvent rub test before release, and we keep a batch record tying every code to the resin lot, the mould, the machine and the inspection result, in both directions. Our supplier audit checklist shows where to test that claim during qualification, and our quality control guide covers the inspection records that sit alongside it.

Frequently Asked Questions