Our organization relies on user generated content for some of our products. Are you aware of any reliable tools or methods for detecting when content has been generated using AI? It's our policy not to incorporate AI generated content in our products.

Depends , whether content is evaluated by Humans or machine. If Humans are evaluating then to some extent it is feasible to identify based on writing style consistency, repetition, content.
AI content may not be factual always however would provide the content confidently. There are some plagiarism checker in the market however I don't know how reliable the tools are.

More on the 'understanding where the source of the response came from' vs a tool... using RAG (Retrieval Augmented Generation) is a common technique to enhance the accuracy and reliability of GenAI models with info fetched from external sources. Some articles on this: What Is Retrieval-Augmented Generation aka RAG | NVIDIA Blogs  and    RAG and generative AI - Azure AI Search | Microsoft Learn