Upton Sinclair wrote in his seminal (and grisly) work The Jungle about conditions in Chicago meatpacking plants: “[Of] all those who used knives, you could scarcely find a person who had the use of his thumb; time and time again the base of it had been slashed, till it was a mere lump of flesh against which the man pressed the knife to hold.” The men who tended to slaughtered sheep had it worse still: “[T]he pelts of the sheep had to be painted with acid to loosen the wool, and then the pluckers had to pull out this wool with their bare hands, till the acid had eaten their fingers off.” Sinclair and the legion of muckrakers working to expose the horrific conditions in the country’s food and medicine manufacturing were the biggest contributors to the passage of the first regulations for the industry.

On this day, June 30, in 1906 Congress passed the Pure Food and Drug act, restricting the manufacture, sale, or transportation of manufactured food products, as well as of medicines with habit-forming substances.

The Pure Food and Drug Act was the companion piece to the Meat Inspection Act, which addressed some of the alarming conditions Sinclair chronicled by providing sanitary standards for meat processing plants, and subjecting all animals to random post-mortem inspections.