What did The Jungle reveal about the meat-packing industry?

The Jungle revealed the unsanitary conditions in the meatpacking industry. Although Sinclair wrote the novel to expose the brutal exploitation of poor immigrant workers, the public reacted most strongly to its depictions of filth in Chicago's meat-packing plants. Audiences were particularly horrified at Sinclair's description of workers falling into rendering vats and becoming part of the ground meat sold to the public as "pure beef lard." 

Though Sinclair hoped his novel would raise outrage over working conditions and treatment of the poor, readers were more concerned with sanitation. As Sinclair would say, he aimed for people's hearts and hit their stomachs. 

The public outcry over conditions in the meat-packing industry led to government inspections of meat-packing facilities and the passage of both the Meat Inspection Act and the Pure Food and Drug Act of 1906. Eventually, reaction to the novel would lead to the formation of the Food and Drug Administration.