All the romaine lettuce in the U.S. is currently unsafe to eat, the Centers for Disease Control and Prevention has said, warning consumers that an E. coli outbreak is linked to the salad staple.

美国疾病预防与控制中心(CDC)近日表示，所有美国长叶莴苣都不能安全食用，并警告消费者大肠杆菌疫情的爆发与以长叶莴苣为主的沙拉有关。

The warning comes after 32 people in 11 states reported E. coli infections. The number of ill people is expected to increase, says Laura Gieraltowski, team lead of the CDC's food borne outbreak response team.

该警告是在11个州共报告32起大肠杆菌感染病例后发布的。美国疾病预防与控制中心食源性疫情应对小组负责人Laura Gieraltowski表示，患者数预计还会有所增加。

Gieraltowski says the CDC took the somewhat extreme measure of warning people to avoid all romaine lettuce because the agency has not yet identified a common grower or supplier that could be the source of the outbreak.

Gieraltowski称，CDC已采取非常措施，以警告人们不再食用生菜，因为该机构尚未确定潜在病源为同一种植者或供应商。

California, which grows the majority of romaine lettuce shipped around the country this time of year, has reported the highest number of E. coli cases in the current outbreak, with 10 people infected so far. Investigators will likely look into those cases to determine where the lettuce came from and where it was sent.

每年的这个时候，加州都会为全美各地提供大量长叶莴苣，而加州所报告的大肠杆菌病例是目前最多的，目前已有10个。调查人员将会追踪这些病例，以确定长叶莴苣的来源与销地。

"Where the cases are can often give us information on how the food was distributed," Gieraltowski says.

Gieraltowski表示：“疫情所在地往往会为我们提供长叶莴苣的分销途径。”

Romaine lettuce itself is not inherently more likely to cause E. coli outbreaks than similar produce. But vegetable row crops, which include leafy greens like romaine, are a major source of E. coli, according to Gieraltowski.

长叶莴苣本质上并不比同类产品更易于造成大肠杆菌感染。但据Gierltowski所述，大肠杆菌主要源于行栽作物，包括长叶莴苣这类带叶蔬菜。

Such crops are responsible for about 40% of E. coli outbreaks.

这类农产品是约40%大肠杆菌疫情的罪魁祸首。