What did the Supreme Court rule in the Munn v. Illinois case?

In the Munn v. Illinois case of 1877, the Supreme Court upheld the authority of states to regulate private industries that affect the public interest, specifically focusing on grain elevator operators in Illinois. The Court ruled that the state had the right to set maximum rates for grain storage and transportation, affirming that businesses operating in the public sphere could be subject to regulation. This decision was significant in establishing the principle that states could intervene in economic matters to protect consumers and ensure fair practices.