Yes. Since many tests look for the most common kinds of allergens, it's possible to have an allergy to something that doesn't show up on a blood test.
Keep in mind that IgE testing can only identify IgE-mediated allergies, and there are a number of food-induced conditions that fall outside that scope. At this time, IgE tests do not diagnose or exclude any condition and are really only a measure of exposure to a specific food.