Consumer concerns about food quality first became prominent long before the advent of GM foods in the 1990s. Upton Sinclair's novel "The Jungle" led to the 1906 Pure Food and Drug Act, the first major US legislation on the subject. This began an enduring concern over the purity and later "naturalness" of food that evolved from a single focus on sanitation to include others on added ingredients such as preservatives, flavors and sweeteners, residues such as pesticides, the rise of organic food as a category and, finally, concerns over GM food. Some consumers, including many in the US, came to see GM food as "unnatural", with various negative associations and fears (a reverse halo effect).