Unless the Florida secretary of state has already approved of including "soup kitchen" among the variety of services that the center will offer at no charge, you must create a separate entity.
You cannot use a DBA for the soup kitchen activities under these circumstances. However, every states formation laws can differ. Make sure to consult with an attorney who specializes in not-for-profit organizations before you take your next step.
Nina L. Kaufman, Esq. is an award-winning New York City attorney, edutainer and author. Under her Ask The Business Lawyer brand, she reaches thousands of entrepreneurs and small business owners with her legal services, professional speaking, information products, and LexAppeal weekly ezine. She also writes the Making It Legal blog.