After reviewing cases of reported outbreaks from 2005 to 2010, the Centers for Disease Control and Prevention found that 2,348 illnesses were linked to imported foods, with half of the cases occurring in 2009 and 2010.
Fish-linked outbreaks were the most common source and nearly 45 percent of all imported foods causing sickness came from Asia, said the CDC report, presented at the International Conference on Emerging Infectious Diseases in Atlanta, Georgia.
Fish caused 17 of the 39 outbreaks, and spices were the next most common with six outbreaks, including five linked to fresh or dried peppers.
"As our food supply becomes more global, people are eating foods from all over the world, potentially exposing them to germs from all corners of the world, too," said lead author Hannah Gould, an epidemiologist in CDC's division of foodborne, waterborne and environmental diseases.
"We saw an increased number of outbreaks due to imported foods during recent years, and more types of foods from more countries causing outbreaks."
US food imports have grown from $41 billion annually in 1998 to $78 billion in 2007, according to the US Department of Agriculture.
Up to 16 percent of all food eaten -- and 85 percent of all seafood -- in the United States is imported.
However, officials suspect that there are more food-linked outbreaks than reported because often people are unaware of what has made them ill.
"We need better -- and more -- information about what foods are causing outbreaks and where those foods are coming from," Gould said in a statement.
"Knowing more about what is making people sick, will help focus prevention efforts on those foods that pose a higher risk of causing illness."
Some 48 million illnesses from food strike the United States each year, with the stomach-ailment causing norovirus being the most common followed by salmonella.
According to the latest data for 2008, there were a total of 23,152 sicknesses that year and 22 deaths.
The CDC defines a foodborne disease outbreak as two or more similar illnesses resulting from the same type of food.