FRIDAY, June 20 (HealthDay News) -- The victim count in the tainted tomato outbreak leaped to 552 Friday even as U.S health officials announced that the salmonella contaminant did indeed come from farms in Florida and Mexico.

The huge increase in victims since the nationwide outbreak began on April 10 appeared largely a result of the state of Texas now reporting 265 illnesses, according to the latest count by the U.S. Centers for Disease Control and Prevention.

At least 53 people have been hospitalized, Ian Williams, chief of the CDC's OutbreakNet Team, told reporters at a mid-afternoon teleconference.

"The FDA is sending teams to Florida and Mexico this weekend to begin inspection of these farms," Dr. David Acheson, associate commissioner for food protection at the U.S. Food and Drug Administration, added. "We are also working with the state of Texas to identify the cluster of illness there."

The increase in people sickened by the singular strain of salmonella saintpaul was not unexpected. Last week, the count was below 200; two days ago, it jumped to more than 380. At least 32 states, plus the District of Columbia, have now reported cases.

On Thursday, health officials had warned that the end was not yet in sight.

"The marked increase is not due to new infections, but mainly because some states improved surveillance in response to this outbreak, and laboratory identification of many other previously submitted strains has now been completed," said Casey Barton Behravesh, an epidemiologist with the U.S. Centers for Disease Control and Prevention, during a Thursday teleconference.

"We are continuing to receive reports of ill people," added Dr. Robert Tauxe, deputy director of the CDC's division of foodborne, bacterial and mycotic diseases. "We do not think the outbreak is over."

On Friday, Acheson said the investigation into the outbreak has now zeroed in on "a number of farms" in both Florida and Mexico.

"These farms along with their associated distribution chains are going to be part of an ongoing investigation," he added, noting, "We do not have a specific farm involved in the contamination; we have to look at the whole chain."

Health officials last week had said that the bulk of the tomatoes available at the start of the outbreak in April had come from Mexico and parts of Florida.

But on Wednesday, Acheson seemed less certain than he has in the past that the exact source would ever be identified. "I have to acknowledge that we may not ultimately know the farm where these came from," he said. "But we're continuing to go flat-out, assuming we are going to get to that point."

Salmonella is a bacteria that can cause bloody diarrhea in humans. Some 40,000 cases of salmonellosis are reported in the United States each year, although the CDC estimates that because milder cases are not diagnosed or reported, the actual number of infections may be 30 or more times greater. Approximately 600 people die each year after being infected.

More information

Visit the U.S. Centers for Disease Control and Prevention for more on the salmonella outbreak.