Recently I had the pleasure of Googling Food Critic.
They are "journalists first" who have an "understanding" of ingredients.
They eat a meal and then form their "opinions". They are "not experts", have "no formal training" and are "not chefs". There are no specific qualifications, degrees or licensing.
As a matter of fact, as long as you can WRITE GOOD, anyone can go into the field of being a food critic!