9 C.F.R. § 590.124
Operating schedules for an official plant shall be subject to approval of the Administrator. The normal operating schedule shall consist of a continuous 8-hour period per day and shall include the time for FSIS inspection program personnel to put on required gear and to walk to a work station, and the time for FSIS inspection program personnel to return from a work station and remove required gear (excluding not to exceed 1 hour for lunch), 5 consecutive days per week, within the administrative workweek, Sunday through Saturday, for each full shift required. Clock hours of daily operations need not be specified in a schedule, although as a condition of continuance of approval of a schedule, the hours of operation must be reasonably uniform from day to day.
9 C.F.R. §590.124