Generally, if the ER physician believes that your illness is related to food prepared at a commercial establishment, then the physician will report the matter to the Public Department of Health. So, if your concern is about this happening to someone else, this is unlikely, given that the Health Department has probably already visited the restaurant.
If you are interested in suing the restaurant for your injuries, pain and suffering, medical bills, lost wages, etc., then you will need a personal injury lawyer.
Many injured persons believe that they can win a personal injury (PI) case against a business without hiring legal representation. However, if the business is insured, then the insurance claims adjuster will, at best, XXXXX XXXXX very low settlement amount. It is overwhelmingly the case that a PI attorney can get you more in settlement from the insurer, even after subtracting the attorney's contingency fees, than you can get yourself. Also, if the insurer knows that there is a lawyer involved, then it will act a lot faster to try to settle the matter. Whereas, if you try to "do-it-yourself," the claims adjuster is likely to stall you indefinitely, in the hopes that you just give up and go away.
For a competent personal injury attorney referral, see this link
Please let me know if I can be of further assistance.