The Food Standards Agency released the last Scottish sheep farm from radioactivity monitoring requirements on 21 June.
Monitoring was imposed in 1987 when raised levels of radioactivity were detected in sheep after the Chernobyl nuclear explosion cast a radioactive cloud over much of Europe.
Some of the radionuclides were deposited in upland areas of the UK. Higher rainfall and local soil conditions increased their uptake by plants and animals.
Restrictions were applied to 73 areas in central and south-west Scotland, permitting sheep to be moved or sold only if their radioactivity levels are within a 1,000 becquerels per kilogram limit.
Originally, 9,700 farms and 4.25 million sheep were designated across the UK. But radioactivity has since declined. Now only 368 farms and 190,000 sheep must still be monitored in England and Wales, mostly in Snowdonia.
Restrictions in Northern Ireland were removed in 2000.