Or rfid tag everything and add a scale so that your fridge can tell when you're out of items or low on milk! Would potentially make recycling easier too
Really, you can predict goods spoilage just given how old stuff is. You don't need a smart fridge; you just need an ETL pipeline from a ScanSnap (reading in your grocery-store receipts) to an inventory tracker app. You've got "smarts", but they're not in the fridge.
(And in the end, that's better: an inventory-tracker app that's on your phone is able to tell you to throw stuff out without you needing to own a "smart-home hub" or configure your fridge to connect to your wi-fi; and, unlike the fridge, its notifications will probably keep working even if its manufacturer goes out of business.)
I can't recall where I came across this idea but how about fridge shelves that (like mini moving sidewalks) slowly move food towards an edge to drop to a lower shelf and eventually to a composter or trash -- the idea being to put food items at a certain spot on a given shelf based on items' expiration date. Wildly impractical IRL, but clever enough to be memorable (for me anyway).
I don't know if its really that bad of an idea, but we didn't allow projects that had been done before so they were all rejected.