Fumaric acid and its calcium, ferrous, magnesium, potassium, and sodium salts may be safely used in food in accordance with the following prescribed conditions:
    
    
        
        (a) 
         The additives meet the following specifications:
     
    
        
        (1) 
         Fumaric acid contains a minimum of 99.5 percent by weight of fumaric acid, calculated on the anhydrous basis.
     
    
        
        (2) 
         The calcium, magnesium, potassium, and sodium salts contain a minimum of 99 percent by weight of the respective salt, calculated on the anhydrous basis. Ferrous fumarate contains a minimum of 31.3 percent total iron and not more than 2 percent ferric iron.
     
    
        
        (b) 
         With the exception of ferrous fumarate, fumaric acid and the named salts are used singly or in combination in food at a level not in excess of the amount reasonably required to accomplish the intended effect.
     
    
        
        (c) 
         Ferrous fumarate is used as a source of iron in foods for special dietary use, when the use is consistent with good nutrition practice.