Foodborne illnesses kill 3,000 Americans every year and make 48 million sick, and most are never identified, US health officials reported on December 15, as Congress prepared a major food safety overhaul.
Norovirus is by far the most common disease-causing germ, accounting for 5.5 million infections a year, or 58 percent of diagnosed illnesses, the federal Centres for Disease Control and Prevention said.
Salmonella, which has caused a number of high-profile nation-wide outbreaks of illness, comes second, causing 1 million infections a year, or 11 percent of the total.
"CDC estimates that each year roughly 1 out of 6 Americans (or 48 million people) gets sick, 128,000 are hospitalised, and 3,000 die from foodborne diseases," the agency said.
Outbreaks of foodborne illness have killed hundreds of Americans in recent years and forced large-scale recalls of foods ranging from ground beef and eggs to peanut butter.
Congress hopes to pass a major overhaul of the U.S. food safety system this week before the session ends.
The legislation would give the government the power to order a food recall and processing plants would be inspected more frequently. The bill covers processed foods, fruit and vegetables but not meat.
Previously, CDC has said that foodborne diseases cause 76 million illnesses, 325,000 hospitalizations and 5,000 deaths in the United States each year. The CDC says the new numbers are more accurate and cannot be compared to past estimates.
CDC experts went through hospital reports and their own food safety program that registers foodborne illnesses and extrapolated the numbers to the total U.S. population for new estimates of how serious the problem is.
They identified 31 major pathogens that caused 9.4 million episodes of foodborne illness and killed 1,600 people. The symptoms caused by most are similar - diarrhea, nausea, vomiting and sometimes fever. Some can cause organ failure - pathogenic E. coli, for instance, can severely damage the kidneys.
After norovirus, sometimes called Norwalk virus, and Salmonella, the three most common causes of illness are bacteria: Clostridium perfringens, Campylobacter and Staphylococcus aureus, the CDC team reports in the journal Emerging Infectious Diseases at www.cdc.gov/eid.
The US Food and Drug Administration called the numbers unacceptable because the illnesses and deaths could have been prevented.
"We must, and can, do better by intensifying our efforts to implement measures that are prevention-oriented and science-based. We are moving down this path as quickly as possible under current authorities but eagerly await passage of new food safety legislation that would provide us with new and long overdue tools to further modernize our food safety program," it said in a statement. Food safety is regulated by a number of agencies including FDA, the US Department of Agriculture and others.