The Lion Quality mark on egg shells and egg boxes means that the eggs have been produced to the highest standards of food safety.

The Lion Quality Code of Practice was launched in 1998 and includes compulsory vaccination against Salmonella Enteritidis of all pullets destined for Lion egg-producing flocks, independent auditing, improved traceability of eggs and a "best-before" date stamped on the shell and pack, as well as on-farm and packing station hygiene controls.

The Lion Quality mark, which is a registered trademark, can only be used by subscribers to the BEIC on eggs which have been produced in accordance with UK and EU law and the Lion Quality Code of Practice.

Approximately 85% of UK eggs are now produced to Lion Quality standards.

Since its introduction in 1998, the Lion mark has been extremely successful so much so that, in 2001 a Government committee (the Advisory Committee on the Microbiological Safety of Food) produced a report highlighting the effectiveness of poultry vaccination in reducing human salmonella cases by half.

This has since been reinforced by the Food Standards Agency which has confirmed the success of the UK egg industry in overcoming salmonella in eggs. In its survey, published in 2004, it tested more than 28,000 UK-produced eggs and no salmonella was found inside any of them.