; and (B) the manufacture of security countermeasures, qualified countermeasures, or qualified pandemic or epidemic products. (2) Required updates The Secretary may require, as appropriate, that the master file holder ensure that the contents of such master file are updated during the time such master file is referenced for a medical countermeasure submission. (c) Sponsor reference (1) In general Each incorporation of data or information within a medical countermeasure master file shall describe the incorporated material in a manner in which the Secretary determines appropriate and that permits the review of such information within such master file without necessitating re-submission of such data or information. Master files shall be submitted in an electronic format in accordance with sections 512(b)(4), 571(a)(4), and 745A, as applicable, and as specified in applicable guidance. (2) Reference by a master file holder A master file holder that is the sponsor of a medical countermeasure submission shall notify the Secretary in writing of the intent to reference the medical countermeasure master file as a part of the submission. (3) Reference by an authorized person A person submitting an application for review may, where the Secretary determines appropriate, incorporate by reference all or part of the contents of a medical countermeasure master file, if the master file holder authorizes the incorporation in writing. (d) Acknowledgment of and reliance upon a master file by the Secretary (1) In general The Secretary shall provide the master file holder with a written notification indicating that the Secretary has reviewed and relied upon specified data or information within a master file and the purposes for which such data or information was incorporated by reference if the Secretary has reviewed and relied upon such specified data or information to support the approval, classification, conditional approval, clearance, licensure, or authorization of a security countermeasure, qualified countermeasure, or qualified