What do the codes stamped on an egg mean?

The stamp is required, standardised and surprisingly informative. It also travels with the egg rather than the packaging, which means it is the only claim you can check after the box has gone in the recycling — useful when an egg has been sitting in the fridge for a fortnight.

Step by step

1. Read the first digit — the farming method.0 is organic. 1 is free range. 2 is barn. 3 is cage, meaning enriched colony cages, since conventional battery cages were banned across the EU and UK in 2012. This one character carries more information than most of the front of the box.
2. Read the country code next.UK for eggs produced in the United Kingdom, or another two or three letter code for imported eggs. Imported eggs are outside the British Lion scheme regardless of how they were farmed.
3. Read the farm identifier.The remaining digits are the unique number of the producer and, on some, the individual laying house. This is the traceability that makes a recall possible — it identifies exactly where that egg came from.
4. Look for the lion.A small red lion printed next to the code means the egg is from the British Lion scheme: the flock is vaccinated against salmonella, the eggs are date-stamped, and there is independent auditing. Laid in Britain is a separate scheme with equivalent assurance. Both matter for raw and lightly cooked eggs.
5. Check the best-before date on the shell.British Lion eggs carry the best-before date stamped on the egg itself, not just on the box. It is set at 28 days from lay by law. That is why a Lion egg is still legible weeks after the box was thrown away.
6. Read the box for the things the shell cannot say.Weight grade — small, medium, large or very large — the packing station code, the best-before date, and any assurance scheme logos such as RSPCA Assured or an organic certifier. The shell tells you the method; the box tells you the size and the packer.

Tips

• If the shell says 1 and the box says something vaguer, believe the shell. The stamp is regulated and specific.
• A missing stamp on a boxed retail egg is unusual and worth questioning. Eggs sold directly by a producer at the farm gate are the main legitimate exception.
• The lion stamp is what allows the FSA to say runny eggs are fine for vulnerable groups. If you are cooking for someone pregnant, elderly or immunocompromised and the eggs are unmarked, cook them through.
• Duck, goose and quail eggs are not part of the Lion scheme and are not stamped in the same way. Treat them all as cook-through eggs.
• Photograph the box code if you are keeping eggs loose in a fridge rack — most of what you lose by decanting is the packing information, not the date.

Common mistakes

• Assuming an expensive box means a better farming method — Branding, colour, size and price are all independent of the method code. A premium-looking box of eggs stamped 3 is a cage egg in nice packaging. The digit is the fact.
• Treating the lion mark as a welfare label — It is a food safety and traceability scheme, principally about salmonella vaccination. It says nothing about how the hen was kept — that is the first digit's job.

Questions people ask