Yes, there have been various reports and urban legends concerning human tissue being found in food products, though these claims are typically sensationalized and not grounded in fact. One of the more notable cases involves the 2004 incident where a fast-food chain faced criticism after a claim arose that human flesh was found in their meat products. Investigations later confirmed that these claims were unfounded.
Another common theme involves the idea of "human DNA" being present in food due to cross-contamination or processing methods, which has been occasionally highlighted in studies that analyze fast food or processed meals. However, this usually refers to trace amounts and is not indicative of any deliberate inclusion of human flesh.
While these stories can be alarming and serve as cautionary tales about food safety, they often tend to stem from misunderstandings or exaggerations rather than actual occurrences. If you're looking for specific documentaries, articles, or fictional stories that touch on this theme, there are many horror stories and media pieces that address the darker side of food production and safety, which may include these kinds of themes.