The massive cyclosporiasis outbreak tied to iceberg lettuce has spread to three additional states, federal health regulators announced Thursday.

The Food and Drug Administration (FDA) said the outbreak — which has been linked to hundreds of hospitalizations and two deaths since illnesses were first reported in July — has now been detected in Georgia, Tennessee and Texas. The FDA added the three states to the outbreak list on Thursday, one week after its previous update, and further state additions remain possible as case reporting typically lags behind the onset of illness given the parasite's roughly week-long incubation period.

According to the agency, 11,458 illnesses have now been reported across 20 states.

Health authorities have traced the multistate outbreak to contaminated iceberg lettuce supplied by Taylor Farms de Mexico to Taco Bell restaurants. Cyclospora outbreaks in the U.S. are frequently linked to imported fresh produce — past federal investigations have traced cases to items such as imported basil, cilantro and raspberries — and the parasite is not commonly transmitted person to person.

The event, one of the largest foodborne illness outbreaks in recent U.S. history, has rippled through the food industry and changed how some Americans shop for fresh produce.

Dave Ciesinski, president and CEO of The Marzetti Company — which owns and operates a range of popular retail food brands, including refrigerated salad dressings — recently told FOX Business that the outbreak is not just hurting lettuce sales but also affecting how Americans shop and eat.

Sales of leafy greens tumbled as much as 30% at the beginning of the outbreak, he said, while vegetable sales fell roughly 16% to 17%, with fruit also declining.

"Suffice it to say, they're changing their behavior," Ciesinski said of consumers during an appearance on "The Claman Countdown."

Michigan has been the hardest-hit state in the outbreak and has reported two related deaths. Both individuals had significant underlying health conditions, according to health officials.

Cyclospora is a single-celled parasite that can cause stomach cramps, nausea, fatigue, weight loss and other health problems, though some infected people remain asymptomatic, according to the U.S. Centers for Disease Control and Prevention (CDC). The CDC notes that cyclosporiasis is treatable with antibiotics, so people with symptoms that persist are advised to contact a health care provider.

The CDC said symptoms typically begin about one week after infection and can last anywhere from a few days to a month. Symptoms can also appear to go away before returning one or more times.

Fox News Digital's James Cirrone contributed to this report.