Olivier salad the dressing — was a jealously guarded secret, but it is known that the salad contained grouse, veal tongue, caviar, lettuce, crayfish tails, capers, and smoked duck, although it is possible that the recipe was varied seasonally. The original Olivier dressing was a type of mayonnaise, made with French wine vinegar, mustard, and Provençal olive oil; its exact recipe, however, remains unknown. At the turn of the 20th century, one of Olivier's sous-chefs, Ivan Ivanov, attempted to steal the recipe. While preparing the dressing one evening in solitude, as was his custom, Olivier was suddenly called away on some emergency.
Mustard (condiment) glucosinolates in mustard plant varieties, and the different isothiocyanates that are produced, make different flavors and intensities. Prepared mustard condiment may also have ingredients giving salty, sour (vinegar), and sweet flavors. Turmeric is often added to commercially prepared mustards, mainly to give them a yellow color. Prepared mustard is sold in glass jars, plastic bottles, or metal squeeze tubes. Because of its antibacterial properties, mustard does not require refrigeration for safety; it will not grow mold, mildew, or harmful bacteria. Mustard can last indefinitely without becoming inedible or harmful, though it may dry out, lose flavor, or brown from oxidation.