The spinach was contaminated with a particularly irulent strain of E. coli bacteria that showed up again recently in ingredients (most likely lettuce) used by some Taco Bell restaurants.

• 原因是该菠菜被大肠杆菌一个特殊的有毒菌株污染了。最近，该菌株又在一些TacoBell餐馆所用的原料（非常像莴苣）中发现。