Did The Jungle achieve its purpose, as noted in Davidson's book?

In Chapter Nine, the author opens with a brief summary of the events leading up to the formation of the new laws. Theodore Roosevelt had come into office in 1904 and was building a reputation as a tough-minded leader. In 1906, an author named Upton Sinclair, a socialist who wanted to show how workers in the meat packing industry were mistreated, published a book called "The Jungle" exposing the often appallingly unsanitary conditions found in the largest packing plants. Rather than raise support for the meat packing workers, the book raised an outcry from the public about the unclean conditions and adulterated meat products the plants put out with little or no standards for sanitation.