Yeah, I would suggest getting a new jar. Five years is a lonnnngggg time. My food philosophy is “When in doubt, throw it out.”
Is it possible, it is the non-meat items you are eating that could actually be causing your distress? @robintemplin found she had to give up vegetables and nuts (fiber containing foods) because it irritated her diverticulosis. (Robin please correct any thing if I misspoke.) Maybe chicken, beef, and eggs would be fine if you weren’t eating plant products?
I am saying this with concern and no judgment, so I hope it doesn’t come across that way, but it may be that your extreme fear of “unnatural” foods may end up being worse for you in the long run than eating some farm raised beef or chicken. Like you mentioned above, even seafood can’t escape being contaminated from something, i.e. PCBs, methylmercury, plastics, and whatever else we’ve pumped into the oceans. If you are breathing, you are getting pollution into your body. It’s just how it is in this world, unfortunately.