Sentence:  A food broker has been defined as an independent sales agent who performs the services of negotiating the sale of food and/or grocery products for and on account of the seller as <WSD>principal</WSD>. 
Meaning of the word marked with <WSD> tags:  A legal person that authorizes another (the agent) to act on their behalf; or on whose behalf an agent or gestor in a "negotiorum gestio" acts.