1. It's not actually a TRUE free market, which is tough to argue but seemingly would invalidate all your next points. I think "free" is a relative term compared to the state-run model of food production.
2. Gluten free bread was not available in your bakery because it was too expensive and customer was unwilling to pay more (markets working). But gluten free bread is available at other retailers (markets working again)
3. Cheap ingredients are bad and more expensive ingredients are worth the extra cost, which is really a value judgement that you are free to make by buying bread from your baker (markets working)
4. Market doesn't regulate "invisible effects" but you don't state any support that the alternative (presumably food czar) would be able to capture "invisible effects"
5. Food safety is more of a concern and better managed by some "food czar" than the individuals effected. When in practice, food safety is better managed by a "last time I ate this I got sick" approach to choice. Food safety is much better in market economies.
Overall, the main problem with your argument is that it compares market conditions to a perfect ideal without any account for cost and practicality