Three more states have reported ill people - Arkansas, North Carolina and Oklahoma.
What is still not known is exactly where the lettuce was tainted by the E. coli.
Nationally, five people have died from E. coli poisoning from the tainted leafy greens; no deaths have been recorded in Texas. On Friday, health officials said they have learned of four more - two in Minnesota and one each in Arkansas and NY.
Health officials have tied the E. coli outbreak to romaine lettuce grown in Yuma, Ariz.
Overall, five deaths have been reported in Arkansas, California, Minnesota and NY.
Officials said that first illness began sometime between March 13 and May 12.
The Centers for Disease Control and Prevention (CDC) said 25 more people had been infected since its last report on 16 May. While almost 90 percent of those who fell ill reported eating romaine lettuce in the week before they were sickened, some told the CDC that they did not personally eat the lettuce but were in close contact with somebody who did.
However, the lettuce from that region is past its shelf life and is likely no longer being sold in stores or served in restaurants, the FDA said.
Some who became ill did not eat the lettuce but had close contact with those who did, the CDC report said.
Symptoms of E. coli vary, but include may include stomach cramps, fevers, bloody diarrhea and vomiting among others. Of 187 people with information available, 89 (48 percent) have been hospitalized, including 26 people who developed hemolytic uremic syndrome, a type of kidney failure. The AP is exclusively responsible for all content.
This story has been corrected to show that the state with two deaths was Minnesota, not California.