Nutritional value
The amounts of various nutrients in mustard seed are to be found in the USDA National Nutrient Database. As a condiment, mustard averages approximately five calories per teaspoon. Some of the many vitamins and nutrients that mustard seeds are high in are selenium and omega 3.

Culinary uses
Mustard is often used at the table as a condiment on meat. It is also used as an ingredient in mayonnaise, vinaigrette, marinades and barbecue sauce. It can also be used as a base for salad dressing when combined with vinegar and/or olive oil. Mustard is a popular accompaniment to hot dogs, pretzels, and Bratwurst. Mustard is also an emulsifier which can stabilize a mixture of two or more unblendable liquids such as oil and water. Added to Hollandaise sauce, mustard can reduce the possibility of curdling.
Dry mustard, typically sold in cans, is used in cooking and can be mixed with water to become prepared mustard.

Storage and shelf life
Because of its antibacterial properties, mustard does not require refrigeration; it will not grow mold, mildew or harmful bacteria. Unrefrigerated mustard will lose pungency more quickly, and should be stored in a tightly sealed, sterilized container in a cool, dark place. Mustard can last indefinitely, though it may dry out, lose flavor, or brown from oxidation. Mixing in a small amount of wine or vinegar will often revitalize dried out mustard. Some types of prepared mustard stored for a long time may separate, causing mustard water, which can be corrected by stirring or shaking. If stored for a long time, unrefrigerated mustard can acquire a bitter taste.

Mustard is a condiment made from the seeds of a mustard plant (white or yellow mustard, Sinapis hirta; brown or Indian mustard, Brassica juncea; or black mustard, Brassica nigra). The whole, ground, cracked, or bruised mustard seeds are mixed with water, vinegar or other liquids, and sometimes other flavorings and spices, to create a thick paste ranging in color from bright yellow to dark brown. Mustard often has a sharp, pungent flavor, as mixing the ground seed with cold liquid allows the enzyme myrosinase which it contains to act on glucosinolates also present to make isothiocyanates, responsible for mustard's characteristic heat. Homemade mustards are often far hotter and more intensely flavored than commercial preparations. A strong mustard can cause the eyes to water, sting the palate and inflame the nasal passages and throat. Mustard can also cause allergic reactions: since 2005, products in the European Union must be labelled as potential allergens if they contain mustard. Commonly paired with meats and cheeses, mustard is also a popular addition to sandwiches, hamburgers, and hot dogs. It is also used as an ingredient in many dressings, glazes, sauces, soups, and marinades; as a cream or a seed, mustard is used in the cuisine of India, the Mediterranean, the Caribbean, northern Europe, the Balkan States, Asia, North America, and Africa, making it one of the most popular and widely used spices and condiments in the world.