Comment by nobody9999

Don't forget red meat either.

In many cases[0][1][2] it's treated with carbon monoxide to make it look redder.

[0] https://pmc.ncbi.nlm.nih.gov/articles/PMC5848116/

[1] https://abcnews.go.com/Business/story?id=3801706&page=1

[2] https://www.foodnavigator-usa.com/Article/2005/11/17/FDA-ask...