The Centers for Disease Control and Prevention is continuing its investigation into a Salmonella outbreak that has now spread to 35 states across the U.S. from an unknown food source.

A total of 419 people have become sick from the Salmonella contamination from June 19 to Sept. 14, 140 people more than were reported on Sept. 23. As many as 66 people were hospitalized for their illnesses. No deaths were reported, the CDC said.

However, the CDC did say that it believes the true number of sick people related to the outbreak is likely much higher than has been reported and may not be limited to the reporting states as many people may have recovered without medical care or testing for Salmonella.

In addition, the agency said some cases may not have been reported yet as the infection takes three to four weeks to determine if a person is sick from the outbreak.

The 35 states the have reported outbreaks from the Salmonella contamination include Oregon, California, Utah, New Mexico, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Texas, Minnesota, Iowa, Missouri, Arkansas, Louisiana, Wisconsin, Illinois, Michigan, Indiana, Kentucky, Tennessee, Mississippi, Alabama, Georgia, Florida, Ohio, New York, Pennsylvania, Maryland, Virginia, North Carolina, South Carolina, New Jersey, Massachusetts, and Connecticut.

While no specific food source has been identified as the cause of the Salmonella outbreak, the CDC previously said it tested food samples from restaurants that contained cilantro and lime that contained Salmonella. The food sample also had onions, but it was not present in the takeout container to test.

While it was unclear which food was contaminated with Salmonella, the CDC did say the bacteria was found in the sample but has not linked it to the outbreak to date.

The CDC has said that the outbreak is “fast-growing” and has urged anyone that has symptoms of Salmonella infection to seek medical treatment and report their illness to their health department to help investigators solve this outbreak.

Symptoms of Salmonella infection include diarrhea that may be bloody, vomiting, and dehydration.

The CDC also reminds consumers to clean hands, utensils, and surfaces often. Fruits and vegetables should also be rinsed before cutting, peeling, or eating. Also, be sure to keep uncooked food away from raw meat, poultry, and seafood. Food that is cooked should be heated to a temperature that is high enough to kill germs. Consumers are also urged to remember to chill perishable foods within two hours.

Salmonella Bacteria Close Up This colorized scanning electron micrograph shows a large grouping of gram-negative salmonella bacteria under a very high magnification of 12000X on Aug. 7, 2009. Photo: Reuters/Handout