Cottage food production operations may only sell, or offer to sell, food items directly to a person, including online and by mail order, or to retail food sales establishments, including grocery stores and restaurants. Food produced from a cottage food production operation, and in compliance with the requirements of this article, shall be considered to be from an approved source, as required of a retail food sales establishment pursuant to department regulations. Any retail food sales establishment, including any grocery store, that sells or offers to sell cottage food products must post signage according to specifications as promulgated by the department indicating that cottage food products are not subject to commercial food regulations or inspection.