This resembles a firefly larva (the linked page shows one example of a locally-abundant species), and while they do not consume vegetables and fruits, they do prey on other organisms that could, like slugs/snails or small insects. We suspect a slug chewed into the tomato and then the firefly ate it, or the larva might just be sheltering there for the time being since it's hidden and damp (firefly larvae need moist environments to thrive). We've sent one of the photos to an Extension entomologist to see if she agrees with this ID, but she's unavailable for the next day or two; if she suggests a different ID, we'll definitely pass that along.

Miri

Thank you Miri! I am glad we let it be, after taking pictures.

You're welcome! (Our apologies for the very slow reply...a system glitch in Ask Extension caused us to receive client replies quite late.)