I particularly like the libertarian idea of independent quality-check companies instead of governmental tax-subsidised beurocrats.

Suppose, I am a chocolate producer. I can benefit only from economy of scale, i.e. selling a lot of chocolate to the public with a better price than my competitors. Now, since it becomes very popular idea to hire an "independent" quality-checker, many customers will prefer to buy chocolate from independently checked company. And because I sell chocolate in huge quantities I can afford to pay a million or so to a quality-checker. After getting me as a million dollar customer and considering competition amongst quality-checking companies we will have yet to see how independent their independent checks are going to be. This sort of things hapening even now in non-libertarian countries like UK or USA. There are examples of sponsored academic research on quality of certain food products that are quite obviously biased towards the sponsor's needs.

Many big companies would prefer to invest bigger money into desinformation of population rather then on safety, quality etc..

Hoping that in libertarian society shenanigans will cease to exist for natural reasons is a little bit naive.