How do government prevent poaching, smuggling, counterfeit, killing, torturing, 25 hours work day, child labor, slavery, etc...? By laws, and enforcing them with a police force, and a justice system. Now do the same with business, and trading, declare them illegal.
You might say that killing is by nature a crime, intrinsically evil and inherently immoral, but that isn't true, nor that business is by nature legal, intrinsically good, and inherently moral. Society decide what is good, and what is evil.
More seriously, communism is not opposed to business, or trading. The idea of communism is to have the mean of production in the hands of community of workers instead of the hands of a little group of persons known a capitalist. A communist workers factory is a business, and will eventually trade to get resources for it's production, and exchange it's product for what it need to exist with other communities. It's the direct control of the work by workers, otherwise known as economic freedom.