What are the Ingredients in McDonald's mustard sauce?
                                
                                
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                                    2 min read                                
                            
                                In 2015, McDonald's officially discontinued its beloved Hot Mustard Sauce in most US locations, leaving a devoted fanbase eager to know exactly what made it so special. The sauce's ingredients include a complex blend of common kitchen staples and preservatives, creating its unique tangy and spicy flavor.