What did Upton Sinclair's book The Jungle cause?

It brought about changes in the way food is prepared and checked in the USA. Before the book was published, the meat packing industry could do almost anything they wanted and put almost anything in meat they wanted to. After the book was published, there were laws passed, and there were changes made, so the food you eat today, and the water you drink today is a lot safer than it was before the book was published.