Oct. 6, 2009 -- High-profile cases of illness due to contaminated beef, such as the 1993 Jack in the Box hamburger outbreaks that killed four children, may be one reason why meat is often framed as the primary culprit of food poisoning.
A new report from the Center for Science in the Public Interest found that a number of food poisoning cases are caused by some unexpected foods, including leafy greens, potatoes and ice cream.
The CSPI report focused on foods regulated by the U.S. Food and Drug Administration. Since the U.S. Department of Agriculture's Food Safety and Inspection Service is responsible for meat and poultry quality control, high-risk foods such as beef and sliced deli meats were not included in the list.
"These are the riskiest foods that are under the purview of FDA," ABC News Senior Health and Medical Editor Dr. Richard Besser said. "Meat products are far riskier than many of these produce products."
In total, 76 million people in the United States get sick and 5,000 people die each year from food-related illnesses.
After reviewing foodborne outbreak data from the CDC where both the pathogen, such as E. coli or salmonella, as well as the food source were known, the CSPI report found that 10 foods regulated by the FDA were responsible for 40 percent of all foodborne outbreaks between 1990 and 2006.
These foods were linked to almost 50,000 illnesses ranging from stomach aches to disability and death.
Researchers noted that the report highlighted the need to update the FDA's safety policies -- as opposed to the USDA's safety policies -- and reduce the number of outbreaks.
"Right now Congress has the opportunity to act decisively on FDA regulations and legislation," said Sarah Klein, lead author of the report from the CSPI. "It could overhaul the way the FDA regulates products."
But the authors pointed out that many cases of illness related to foodborne pathogens often go unreported, meaning the number of outbreaks could be higher than their estimates.
The following is a list of foods compiled by the CSPI as some of the riskiest when it comes to potential contamination.
"No single USDA product has caused as many outbreaks as leafy greens," Klein said.
While this may seem fantastic in light of how the number of meat-related outbreaks far outstrips any other food product, Klein pointed out that in many cases the food source of the outbreak remains unclear. For example, food poisoning following a hamburger lunch could be a result of the meat patty, contaminated lettuce or rancid mayonnaise.
The CSPI reported that leafy greens, including spinach, lettuce and cabbage, were responsible for 363 outbreaks between 1990 and 2006 and caused 13,568 cases of illness.
Bagged spinach contaminated with E. coli raised concerns in 2006 after a number of deaths and illness were reported following consumption, but leafy greens are susceptible to contamination by salmonella as well.
Greens may become contaminated, according to the report, upon contact with animals or manure and through poor handling.
"One contaminated head of lettuce or spinach thrown into a washing tank sees the pathogen in the wash water," Klein said. "And that spreads to an entire day's production of leafy greens."
The CSPI reported 352 outbreaks involving 11,163 cases of illness due to eggs contaminated primarily with salmonella, a bacteria that often causes diarrhea.
If eggs are not contaminated with salmonella before it is formed in a chicken, then undercooking, allowing the eggs to sit at room temperature, or cross contamination in the home or in a restaurant are a few of the major ways in which eggs can cause illness, according to Keith-Thomas Ayoob, an associate professor in the department of pediatrics at the Albert Einstein College of Medicine in New York City.
The report noted that prisons, restaurants and catered events were a few of the primary egg-related illness offenders.
"Eggs can have microscopic cracks too," which could allow for contamination after the egg is produced but before it is broken and used, Ayoob noted.
Still, Ayoob said eggs are generally safe foods and the chances of getting salmonella from an egg that has been properly stored and cooked is about one in 20,000.
Tuna fish was linked to 268 outbreaks and 2341 illnesses, according to the CSPI report.
The most common complaint was scombroid illness due to scombroid toxins, which are linked to fresh water fish and can occur in tuna that is left in a warm place too long. Side effects of ingesting scombroid toxins include flushing, nausea and cramps.
"Scombroid toxin is more likely in fresh or raw tuna than in processed varieties, such as canned tuna," said Caroline Smith DeWaal, food safety director for the Center for Science in the Public Interest and another author of the report. "Scombroid toxin can't be cooked away. The toxin may still be in cooked fish."
Ayoob pointed out that outbreaks associated with tuna could have other elements such as rancid mayonnaise in tuna salads. If, for example, tuna is purchased from a store or deli, it may have been sitting out at room temperature, allowing toxins and bacteria to accumulate.
This salt-water delicacy was the cause of 132 outbreaks and 3,409 reported illnesses, the CSPI report said.
"How much of that was eaten raw? If it's raw, you're on your own there," since the risks of eating raw or undercooked foods, including seafood, are well known, Ayoob said.
According to the CSPI findings, most of the oyster outbreaks occurred in restaurants and the most common pathogens were norovirus and vibrio. Norovirus, which causes acute stomach distress including vomiting, diarrhea and cramps, is related to poor food handling but it is also water-borne, which makes oysters particularly vulnerable to the virus.
Vibrio, a bacterium in the same family as cholera, is less common than Norovirus but more dangerous.
"[Oysters are] not consumed by many, but they do cause a large number of outbreaks and when those outbreaks occur, they can be large," DeWaal said.
It may seem impossible to get sick from this most basic, starchy root, but potatoes caused 108 outbreaks between 1990 and 2006, resulting in 3,695 cases of illness.
However, DeWaal noted that the problem, typically, is not the potato itself. Instead, cross contamination during food preparation is a likely source of blame since potatoes are a component of many recipes rather than a stand-alone food.
In such cases, Salmonella is associated with almost 30 percent of potato outbreaks, as well as the bacteria listeria, which is associated with deli counters, kitchen areas and cold salads.
Ayoob pointed out that potatoes are often used in salads with mayonnaise, which has a high risk of going bad if left unrefrigerated for a period of time.
"In the home is where consumers have a lot of control," Ayoob said, stressing washing and separate cutting boards to prevent cross-contamination between meat, dairy and produce.
"Even if foods did cause an outbreak, at home, to some degree, it could be prevented," he said.
Salmonella was the most common hazard among cheese products, responsible for 83 outbreaks and 2,761 reported illnesses.
Cheeses are susceptible to contamination because they are made using many steps, including curdling, salting, and processing. Using pasteurized milk that has been heated to kill pathogens has reduced the number of harmful bacteria in cheese.
The report stressed that certain people, such as pregnant women, should be wary of soft cheeses like brie or camembert because they are more likely to contain the harmful listeria bacteria, which has been linked to miscarriage.
Hearts might sink to see ice cream on a list of risky foods, but the CSPI reported that it was responsible for 74 outbreaks and 2,594 reported illnesses.
DeWaal said salmonella, possibly the result of using contaminated eggs as part of the ice cream pre-mix, is one risk. In fact, contaminated pre-mix from unpasteurized eggs was the reason a large outbreak occurred in 1994.
Soft ice cream is still another risk, because of the chance of listeria contamination.
Ayoob pointed out that in ice cream stores, good food handling practices, such as keeping scoopers clean, are essential to avoid contaminating ice cream.
"It's usually not the ice cream but what people did to it," Ayoob said.
Tomatoes are frequently linked to foodborne illnesses and they are suceptible to contamination because they are often eaten raw instead of being cooked to kill bacteria, and together with other foods, such as salad greens, where it is easy for pathogens to spread.
There were 31 outbreaks involving tomatoes recorded between 1990 and 2006, which resulted in 3,292 illnesses. Salmonella contamination was responsible for more than half of these outbreaks and norovirus was the second most common contaminant.
But DeWaal pointed out that although fresh produce can be a risk for contracting a pathogen, eating fruits and vegetables is important because "these foods are too ubiquitous and too good for you."
Ayoob agreed and suggested cutting fruits and vegetables before preparing meats, using separate cutting boards for both, and washing everything that touched the meat -- including the sink faucet -- thoroughly and often, to keep pathogens at bay.
The CSPI report identified sprout seeds as the primary source of contamination for a germinated sprout.
Improper handling can spread pathogens to uncontaminated plants. Salmonella is common to sprouts, as is E. coli. The CSPI reports that contaminated sprouts have caused 31 outbreaks and 2,022 reported cases of illness.
The researchers note that the warm, humid conditions sometimes used to encourage seeds to germinate can lead to bacterial growth -- a problem that they say new legislation could resolve.
"CSPI's real concern is helping the FDA to regulate foods" DeWaal said. "They don't have mandatory food safety plans -- or frequent inspection -- they do it sporadically, but they don't do it consistently."
Strawberries, blackberries and raspberries are just a few of the fruits the CSPI flagged as having contributed to 25 outbreaks between 1990 and 2006, causing 3,397 illnesses.
While these fruits may surprise some by their presence on a list of risky foods, DeWaal said the result did not surprise her as the CSPI has known for years about the potential for berries to be contaminated with pathogens.
Perhaps the most serious case was in 1997, when more than 2.6 million pounds of strawberries became contaminated with Hepatitis A, a virus that causes liver inflammation. The contamination occurred after an infected factory worker in Baja California, Mexico, handled the fruits, and the outbreak prompted a strawberry recall.
"That was a disaster," Ayoob said. "That kind of thing does put everyone on guard, however. It helps food producers and handlers enforce penalties and laws."