In any case in which you’re claiming negligence, four elements must be established: (1) duty (2) breach of that duty (3) causation of harm, and (4) damages.
I’m assuming you have duty and breach of duty here. However, without any significant damages, there’s no case. You must have all four elements.
Legal purists can correctly point out that I’ve simplified the analysis. However, this is an accurate summary and this format doesn’t have room for the volumes that have been written on the breakdown of causation, the two places in which we can plug in foreseeability, and other issues.
This answer is provided for informational purposes only. Actual legal advice can only be provided in an office consultation by an attorney licensed in your jurisdiction, with experience in the area of law in which your concern lies.
It's disgusting, but I can honestly say I wouldn't take the case unless you had very, very solid evidence of related damages. If it happened to me and the only damage was that I was "grossed out", I'd get the store manager to give me a bunch of free coupons and use them at a different location. That's just my two cents - I wouldn't make a final, legal determination on the claim unless we had a consultation.
Ohio does have a state statute that prohibits the sale of "adulterated" food, which includes contaminated food. Your facts raise several issues - how did the gaze get in the fries, did it cause you significant illness and pain, and did you timely seek necessary and reasonable medical care. If your only expense was the loss of the fries, without any significant illness or necessary medical treatment, then your "case" is really only worth the price of the contaminated fries. I would forget it if no significant illness. If you did suffer a significant illness that required medical treatment, then consult with an attorney for a possible legal claim.
When I was just out of law school a client claimed they drank a softdrink and felt something in their mouth. they spit it out and it was a worm. This was during a spaghetti dinner which was promptly thrown up. I rember we recovered $300. But that was when I was just a newbie.
There is a special statue on this which makes it easier to prove a claim for damages. The best thing is to always talk with a laywer. Also save the evidence. You may be able to resolve this yourself if no lawyer wants to help you.