“U.S. Fancy” consists of grapefruit which meet the following requirements:
    
    
    
    
        
        (i) 
         Not more than one-tenth of the surface, in the aggregate, may be affected by discoloration. (See  § 51.638.)
     
    
    
    
        
        (4) 
         Similar varietal characteristics;
     
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
        
        (d) 
         Not damaged by any other cause.
     
    
        
        (e) 
         For tolerances see  § 51.628.