When you add "보다" to the verb form, it takes on the meaning of "try this action". So 먹어보다 (먹어보세요) means to try eating something.
What I'm wondering is why "Taste this food" got marked wrong for me, when the lesson notes state that "taste" is a proper translation too...
보다, when suffixed after another verb stem and 아/어, doesn't mean "to see," but "to try". 먹어보다 is then "to try by eating", which in English is reduced to simply "try (a food)". So, all this sentence means is "Try this food", even literally.