How do we know/find the exact expiration date of products?

Question

Edit: I don’t mean how the consumers know when the product has expired but how those who create the products also create the expiration dates that we see written.

In: 1

Answer 1

Usually when a food product is shipped a few samples are kept in storage as Remains. Over time the remains are analyzed for things like bacterial/fungal growth, preservative concentration, pH, etc. By tracking how these qualities change over time the best by date can be adjusted for future product runs.