Garlic is high in sulphur. Mercury binds to sulphur strongly.

Sulphur is a mercury chelator which will mobilize mercury and can cause symptoms to appear if the bonds break in the blood or in the intestines. You can use Algin to prevent mercury from being reabsorbed into the blood from the intestines when eating high-sulphur foods or taking chelation agents.

Here is an article that may help:

http://mercurytalk.com/wiki/index.php/List_of_Foods_That_Contain_Sulphur

http://mercurytalk.com/wiki/index.php/List_of_Preservatives_That_Contain_Sulphur