Most processing plants that make bulk foods like breads ,Bagels ,pizza crust ,different Dough's, cake batters and flour, use the very same assembly line to prepare other Foods as well. That's why most boxes or anything you consume rather has a label that says his product may contain soy and egg products. Or it will have a label saying something along the lines of " the factory where this product was made also makes products that contain peanuts or nuts and soy" so even if the food you're eating does not contain any of these ingredients it was made on the same table as the very ingredients you are allergic to. The only real way to be safe is if you buy locally from somebody that owns only makes one thing and then you buy something else from somebody that makes only one thing and so on.
It is to be expected at any bagel place...
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