Puhcture pork loin well with a fork on all sides, 20 or 30 times in all, then place in a nonreactive dish just large enough to hold it.
Grate zest off the limes on the finest holes of a grater, then halve the limes and squeeze their juice into a small saucepan. Add the grated zest and the marmalade. Add salt and pepper to taste. Cook gently over a low flame, stirring well, until marmala