How would I go about getting a food product I invented sold in grocery stores?

Answer 1

It's pretty difficult. There are a number of health an safety laws you'd have to follow. And most grocery stores or chains would require you to have at least a million dollar liability insurance policy to cover any possible mishaps/lawsuits.

Answer 2

If you can produce it yourself, then you could talk to the individual stores or companies yourself (or with a lawyer) to set up merchandising. If you cannot produce it yourself, you can license it to a company who can and pick up payments from them.

Either way, you need to consult a lawyer.