Your premise is flawed: if it was true that without government, companies would just carelessly or intentionally poison us all (not a good way to gain repeat customers btw) then I would agree with you. But obviously I disagree with your premise.
The Jungle is a widely misunderstood book. For one, it's fiction [1] [2] [3].
The milk scandal is interesting tho. I don't disagree that there are people/companies out there that are horrible human beings (or run by horrible human beings), but these are exceptions. There is also a market-based recourse for consumers. Lawsuits and liability is a big deterrent for example. It's also illegal to harm someone (as it should be) so jail time for the offenders is quite possible without having enormous and onerous regulations. And haven't you noticed that it's the giant companies that often push regulation? Because it raises barriers to entry for competitors. Big companies have the resources they need. Using the government to hurt your competitors is one of the oldest traditions in countries with governments big enough and powerful enough to do so.
And they got the crap sued out of them. The lying is the problem IMHO. People know what they're getting now, but millions still choose to smoke. And why shouldn't they be able to?
Companies are careless and malicious despite government and customers actions.
* XIX century wants it's snake oil back
* Didn't hear about China and melamine milk scandal?
* Would you buy food from Amazon if it was co-mingled in current way?
* VW emission scandal
It is easy to be freetard when you do not get diarrhea every so often due to food that was "optimized" (like in XIX century ;)
So we should stop government from enforcing food safety and accept poisonings as fact of life...