Foodborne illnesses continue to be a major problem in the United States, despite a decrease in the number of Salmonella cases in recent years, the Centers for Disease Control reported. CDC's report card on foodborne illnesses found an increase in illnesses from bacteria in raw or undercooked shellfish, according to the Associated Press.

The CDC reported that the rates of illnesses are due to Vibrio, a bacterial toxin found in shellfish. Infections have increased by 75 percent since the CDC's previous analysis period, 2006-2008. It is reportedly the highest the CDC has ever seen since they began tracking the disease in 1996. 

"Vibrio infections have continued to increase as they have in the past," said Dr. Robert Tauxe, the Deputy Director of the CDC's Division of Foodborne, Waterborne, and Environmental Diseases. "We are at the highest level observed since our tracking began in 1996."

Tauxe said many Americans have become sick from food in 2013. He estimated that every year, one in six people in the United States become sick from eating contaminated food. Salmonella was considered the top cause of foodborne illness last year based on a CDC's 2012 report card on food poisonings. Campylobacter bacteria commonly linked to raw milk and poultry comes in second place, according to the AP. Other foodborne diseases include listeria, shigella and E. coli,

Salmonella is a bacterium that can cause diarrhea, cramps and fever and sometimes chills, nausea and vomiting for up to seven days. In 2013, Salmonella infections fell by nine percent, compared with the rate in 2010-2012, but still accounts for over 30 percent of all cases,

Campylobacter infections have risen 13 percent since 2006-2008 and have remained stable over the past five years. In 2013, the CDC's food poisoning report recorded over 19,000 infections, 4,200 hospitalizations, and 80 deaths from foodborne illnesses out of 48 million people in 10 states.

The report was published in the CDC's Morbidity and Mortality Weekly Report.