I'm going to have to agree with Rei on this. Only after hours of observation did I come to the conclusion that the things I gathered were safe to consume. After that, each one was given a thorough washing.

But as for the food, I haven't been able to actually examine the evolution of this place. To be quite honest, it's hard to say just how much this world mirrors many aspects of Earth, if at all. So far, despite the fact that the animals are different... well, some of them, plant life and water still functions the same. In fact, we should be quite glad we have drinkable water on this planet. That is truly what will allow us to survive.

[And Ami had no real desire to become a water mill to ensure everyone had some.]