The reason satire can be so hard to distinguish is explained in
Poe's Law. However ridiculous a fundamentalist parody is, there's always the possibility they're seriously that crazy. Without an obvious joke, or knowing the author, there's really no way to distinguish. The best way to distinguish is to look for those obvious jokes.
News involving verifiable facts (Spaghetti harvest) are easier to distinguish, because it's a proven fact that spaghetti isn't directly harvested from plants. An article about Congress passing a bill about spaghetti harvest would be more difficult to distinguish, because people can actually be that ignorant.