Floors in food preparation areas are to be constructed of concrete, asphalt, tight wood or other similar cleanable material kept in good repair. Dirt or gravel, when graded to drain, may be used as subflooring, when covered with clean removable platforms or duckboards, or covered with wood chips, shavings, or other suitable materials effectively treated to control dust.
N.Y. Comp. Codes R. & Regs. Tit. 10 §§ 14-2.13