In the United Kingdom, preparations of ketchup were historically and originally prepared with mushrooms as a primary ingredient, rather than tomatoes.[12][13][14] Ketchup recipes began to appear in British and then American cookbooks in the 18th century. In a 1742 London cookbook, the fish sauce had already taken on a very British flavor, with the addition of shallots and mushrooms. The mushrooms soon became the main ingredient and from 1750 to 1850 the word "ketchup" began to mean any number of thin dark sauces made of mushrooms or even walnuts.[15] In the United States, mushroom ketchup dates back to at least 1770, and was prepared by British colonists in the Thirteen Colonies.[16] In contemporary times, mushroom ketchup is available in the UK, although it is not a commonly used condiment.[17]