Under Section 304 of the Tariff Act of 1930, as amended, most products entering the United States must be clearly marked so that the "ultimate purchaser" can identify the country of origin. Imported meat products are subject to this requirement: imported carcasses and parts of carcasses must be labeled, and individual retail (consumer-ready) packages also must be labeled. Imported carcasses or parts generally go to U.S. plants for further processing. The labelling policy considers these plants as the "ultimate purchasers." Therefore, any products these plants make from the imported meat (for example, ground beef patties made in the United States from beef that originated in Canada or elsewhere) do not have to bear country-of-origin labels. A number of other agricultural articles are exempt from the basic country-of-origin labelling requirements: eggs, livestock and other animals, live or dead; and other "natural products" such as fruits, vegetables, nuts and berries. (However, the outermost containers used to bring these articles into the United States must indicate the country of origin.) There is an interest among U.S. farmers to require more extensive labelling of agricultural products (especially meats and produce). At issue are whether consumers would be more likely to buy the U.S. alternative if such labelling is more prevalent and whether foreign countries might view such a change as a nontariff trade barrier.