Four additional people have been killed and hundreds have fallen ill due to an E. coli outbreak from romaine lettuce, the Atlanta-based Centers for Disease Control and Prevention announced Friday.

The deaths occurred in California, Pennsylvania, Arkansas, Minnesota and New York, according to the CDC. One person was reported to have died from the outbreak in early May. The update from the CDC comes two weeks after the center said that any romaine lettuce now available for sale should be safe.

The CDC said that the newest cases were likely people who had eaten romaine lettuce while produce from the Yuma region was still available in stores.

"Most of the people who recently became ill ate romaine lettuce when lettuce from the Yuma growing region was likely still available in stores, restaurants, or in peoples' homes," the CDC said in its update Friday. "Some people who became sick did not report eating romaine lettuce, but had close contact with someone else who got sick from eating romaine lettuce."

» RELATED: Concerned about E. coli? Here's how to keep your food safe from the bacteria

At least one Georgia case was recorded as part of the outbreak when a Metro Atlanta teenager was hospitalized in April. The teen was not identified and has been released from the hospital.

Nearly 200 people from about 36 states have been sickened by the outbreak that was first discovered in mid-March, reports The Washington Post. Nearly half of the people sickened by the E. coli have been hospitalized, according to the CDC.

Around 26 people developed hemolytic uremic syndrome, a form of kidney failure that can be life-threatening to someone with weakend immune systems such as children and the elderly, according to The Post. The majority of people who fell ill from the outbreak live in California.

E. coli is a group of bacteria that's found in foods, the environment and in your intestines, according to the CDC. While most strains of E. coli won't make you sick, others can cause a variety of illnesses, including diarrhea, urinary tract infections and respiratory issues.

This latest E. coli outbreak marks the worst since 2006, when around 205 people became ill and five died after contracting E. coli from baby spinach, according to The Post.

Federal investigators have determined the E. coli came from contaminated lettuce grown in Arizona’s Yuma region but they have not been able to link the outbreak to a specific farm.