All food, before being placed in a locker shall be quick or sharp frozen in a quick or sharp freeze room, unless the locker room temperature is maintained at not more than the maximum temperature required by sections 196.450 to 196.515 for a quick or sharp freeze room. No food shall be placed in a locker unless previously inspected by the operator and each portion shall be wrapped and be marked or stamped showing contents, correct locker number and date of wrapping. All fruits and vegetables shall be prepared by an approved method before being quick or sharp frozen.