Federal health officials warn you not to eat any romaine lettuce unless you know where it’s from, as the  E. Col outbreak has spread throughout the country. The  CDC advisory now includes whole heads and hearts of romaine lettuce, along with chopped and bagged romaine and salad mixes that include romaine.

At least 64 people in 16 states have been infected with the same strain of E. coli linked to romaine lettuce. About half—31 of them—have been hospitalized.

The CDC says most people develop symptoms like diarrhea, severe stomach cramps, and vomiting, and recover within a week. But five people sickened in this outbreak have suffered from a form of kidney failure called hemolytic uremic syndrome (HUS).

“What’s concerning me at this point is there’s an unusually high hospitalization rate,” said Bill Marler, a food safety lawyer.

Additionally, the CDC says that restaurants and retailers should “not serve or sell any chopped romaine lettuce, including salads and salad mixes containing chopped romaine lettuce from the Yuma, Arizona growing region,” and they should ask suppliers where their romaine lettuce comes from.

If you’re wondering when you can start eating all the romaine lettuce again without fear, the answer is: hang tight.

Earlier this month the CDC declared that: “Leafy greens typically have a short shelf life, and since the last illness started a month ago, it is likely that contaminated leafy greens linked to this outbreak are no longer available for sale.”

But until the E. Coli outbreak is OFFICIALLY cleared, try to swap with greens such as kale, arugula, or spinach which have a much higher nutritional value.