Bad sulphur allergy

Just had a bad allergic reaction last night! Rash still on my face. Have eaten their burger patties before without this reaction. Was not aware that they now add Sulphur dioxide to there patties and other meat , such as their kebabs etc. So much for their promise of freshness. Sulphur allergies can be very severe and it should not be widely used in meat. I do not know when they started adding this , or if they have increased the amount used, but did not expect it . To people more sensitive than me could possibly be even more severe. Should have put on face of packaging that they now add this horrid chemical. I , personally do not feel the use of this substance is very ethical. Could not get hold of them for info . Tried for hour . Feel that public must be warned.