The Electronic Product Code (EPC) is a Radio Frequency IDentification (RFID) that offers a new way of automating identification. However, once RFID tags carry more than just an identifier, privacy may be violated. Treating the privacy in early stages helps to master the data view before interpreting and storing it in databases. An RFID middleware is the entity that sits between tag readers and database applications. It is in charge of collecting, filtering, aggregating and grouping the requested events from heterogeneous RFID environments. This way, the RFID middleware is the central point for both data and configuration access. Thus, the system, at this point, is likely to suffer from parameter manipulation and eavesdropping, raising privacy concerns. We propose a privacy controller module that enhances the Filtering and Collection middleware of the RFID EPCglobal network. We provide a privacy policy-driven model using some enhanced contextual concepts of the extended Role Based Access Control model. To show the feasibility of our privacy-enhanced model, we provide a proof-of-concept prototype integrated into the middleware of the Fosstrak framework, an open-source implementation of the EPCglobal specifications.