Do you perform food challenges after starting Xolair for IgE-mediated food allergy to ensure efficacy?

If so, what protein dose do you select and do you perform to each food to which the patient is allergic? Questioning whether to use the primary endpoint of 600 mg or the secondary endpoint of 1,000 mg. A similar question is found here about an OFC prior to initiating Xolair for food allergy.