经过调查后，Riviera Farms 和维州卫生当局终于确定问题菠菜的污染源头，是由一种名为“刺苹果”（thorn apple，又称jimsonweed）的有毒野草污染。

Jimsonweed, also known as Datura, is a member of the nightshade family. It is extremely toxic and should never be consumed. The plant can cause severe hallucinations, confusion, and even death.