What do strawberries and oysters have in common? Both make the list of the top ten foods responsible for the most outbreaks of foodborne illness since 1990 in the United States. Oysters, okay–but berries?
A century ago, typhoid fever, tuberculosis and cholera were the common foodborne diseases. Improvements in food safety (think pasteurization, safe canning, disinfection of water supplies) have conquered those diseases–but a host of other foodborne diseases have stepped up to the plate, so to speak, to take their places. Foodborne disease outbreaks are currently responsible for tens of millions of illnesses, hundreds of thousands of hospitalizations, and thousands of deaths every year in the United States.
The Center for Science in the Public Interest (CSPI) published their report of the top ten riskiest foods (FDA Top Ten) overseen by the Food and Drug Administration (FDA). The FDA is responsible for regulating produce, seafood, egg and dairy products, as well as packaged foods such as cookie dough and peanut butter. The FDA regulates nearly 80 percent of the American food supply. From the CSPI, here they are–followed by precautions from the CDC on how to reduce the risk:
1. LEAFY GREENS: 363 outbreaks involving 13,568 reported cases of illness
Salads and other leafy greens (iceberg lettuce, romaine lettuce, leaf lettuce, butter lettuce, baby leaf lettuce, escarole, endive, spring mix, spinach, cabbage, kale, arugula or chard) account for 24 percent of all of the outbreaks linked to the FDA Top Ten. The very leaves we’re supposed to be eating to improve our health! E. coli accounts for 10 percent of all outbreaks in leafy greens; Norovirus, which is commonly spread by the unwashed hands of an ill handler or consumer was linked to 64 percent of the outbreaks in leafy greens. Salmonella was responsible for nearly 10 percent of the outbreaks.
But you should still eat your greens! Read why in Go Gorgeous Greens.
2. EGGS: 352 outbreaks involving 11,163 reported cases of illness
The overwhelming majority of illnesses from eggs are associated with Salmonella. Regulations for cleaning and inspecting eggs were implemented in the 1970s and have reduced salmonellosis caused by external fecal contamination of egg shells. However, Salmonella enteritidis, the most prevalent type of Salmonella in eggs today, infects the ovaries of otherwise healthy hens and contaminates the eggs before the shells are formed. Notably, final regulations that require the adoption of controls aimed at minimizing Salmonella enteriditis in egg production were issued in July 2009 (and will become effective in 2010 or 2012, depending on producer size), after over a decade of inaction by the federal government. Half of all egg outbreaks occurred from restaurants and other food establishments.
For more on what egg labels mean, see Easy Greening: Organic Eggs.
3. TUNA: 268 outbreaks involving 2341 reported cases of illness
Scombroid, the illness caused by scombrotoxin, was by far the most common cause of illness related to tuna dishes, affecting over 2300 people who were reported to have been sickened. Fresh fish decay quickly after being caught and, if stored above 60F degrees, begin to release natural toxins that are dangerous for humans. Adequate refrigeration and handling can slow this spoilage, but the toxin cannot be destroyed by cooking, freezing, smoking, curing, or canning.
Symptoms of scombroid poisoning can include skin flushing, headaches, abdominal cramps, nausea, diarrhea, palpitations, and loss of vision. In addition to scombrotoxin, Norovirus and Salmonella caused illnesses related to tuna consumption, affecting nearly 1000 people. Over 65 percent of outbreaks linked to tuna occurred in restaurants.
Read more on seafood in Safe, Sustainable Fish.
4. OYSTERS: 132 outbreaks involving 3409 reported cases of illness
Though they comprise a trivial part of the American diet, tainted oysters are the fourth entry in the FDA Top Ten, responsible for almost 2000 reported illnesses. Not surprisingly, the majority of outbreaks from oysters occurred in restaurants.
Illnesses from oysters occur primarily from two sources: Norovirus and Vibrio. Although Norovirus in other foods is usually associated with improper handling during harvest or preparation, oysters can actually be harvested from waters contaminated with Norovirus. When served raw or undercooked, oysters can cause gastroenteritis, an inflammation of the stomach and small or large intestines.
The most dangerous of the two pathogens found in oysters is Vibrio. This hazard is a type of bacterium in the same family as cholera. The most common strains in the U.S. are V. vulnificus and V. parahaemolyticus, both of which can cause severe disease. In immuno-compromised persons, particularly those with chronic liver disease, V. vulnificus can infect the bloodstream, causing a severe and life-threatening illness characterized by fever and chills, decreased blood pressure (septic shock), and blistering skin lesions. V. vulnificus bloodstream infections, called septicemia, are fatal about 50 percent of the time.
For an interesting take on oyster-eating, read Hey Vegans, Consider the Oyster.
5. POTATOES: 108 outbreaks involving 3659 reported cases of illness
Potatoes, often in the form of potato salad, were linked to 108 outbreaks, with more 3600 consumers reported to have been sickened by spuds since 1990.
Potatoes are grown in the soil, but they are always cooked before consuming. Outbreaks are linked to dishes, like potato salad, that can contain many ingredients and also a broad range of pathogens. Salmonella is most common, associated with almost 30 percent of potato outbreaks. E. coli also appears in the potato category, accounting for 6 potato outbreaks. Normally found in animal feces, the presence of Salmonella and E. coli in potato dishes could indicate cross contamination from the raw to the cooked ingredients or possibly from raw meat or poultry during handling and preparation. Shigella and Listeria monocytogenes also appear in outbreaks associated with potatoes. Shigella is easily transmitted from an infected person to a food product, and thus may indicate improper handling during preparation.
6. CHEESE: 83 outbreaks involving 2761 reported cases of illness
Cheese products were linked to 83 outbreaks that sickened thousands of consumers since 1990, making it number six of the FDA Top Ten. Salmonella was the most common hazard among cheese products.
Cheese can become contaminated with pathogens during the initial phases of production (curdling, molding, and salting), or later during processing. Most cheeses are now made with pasteurized milk, lowering the risk of contamination with milk-borne pathogens. However, as recently as August 2009, California officials warned consumers about eating Latin American-style cheeses (such as queso fresco, queso oaxaca, and others), which may be made by unlicensed manufacturers using unpasteurized milk that could contain harmful bacteria.
Pregnant women should be particularly cautious about consumption of soft cheeses (such as feta, Brie, Camembert, blue-veined, and Mexican-style cheese), which can carry Listeria. Linked to at least four outbreaks from cheese since 1990, listeriosis is vastly under-reported, since overt symptoms of infection can be mild in those who are not particularly at risk. Outbreaks from cheese products occur most frequently in private homes.
Considering giving up cheese? Check out 11 Reasons to Stop Eating Dairy.
7. ICE CREAM: 74 outbreaks involving 2594 reported cases of illness
The largest ice-cream outbreak in history occurred in 1994, when a popular ice cream manufacturer used the same truck to haul raw, unpasteurized eggs and pasteurized ice cream premix. Contaminated with Salmonella en route to the plant, the premix was not pasteurized again before being incorporated into ice cream products. The result: thousands of people sickened in 41 states.
Soft ice cream can be a particular hazard to pregnant women and others who are more susceptible to listeriosis. A particularly hardy bacterium, Listeria can survive on metal surfaces–such as the interior of soft ice cream machines–and may contaminate batch after batch of products. Almost half of all ice-cream outbreaks contained in CSPI’s database occurred in private homes. This is most likely due to the use of undercooked eggs in homemade ice cream. So…make some healthy homemade popsicles instead!
8. TOMATOES: 31 outbreaks involving 3292 reported cases of illness
In 2005 and 2006, tomatoes were implicated in four large multistate outbreaks of Salmonella, sickening hundreds of people across the country. Tomatoes may have been wrongly implicated in a sweeping 2008 outbreak (later linked to fresh jalapeno and serrano peppers), tomatoes have caused at least 31 identified outbreaks since 1990. The most common hazard associated with tomatoes is Salmonella, which accounted for over half of the reported outbreaks. Salmonella can enter tomato plants through roots or flowers and can enter the tomato fruit through small cracks in the skin, the stem scar, or the plant itself. Once inside, destruction of Salmonella without cooking the tomato is very difficult. Norovirus was the second-most common hazard. Restaurants were responsible for 70 percent of all illnesses associated with tomatoes.
9. SPROUTS: 31 outbreaks involving 2022 reported cases of illness
Raw and lightly cooked sprouts have been recognized as a source of foodborne illness in the U.S. since the 1990s. Since 1999, CDC and FDA have recommended that persons at high risk for complications of infection with Salmonella and E. coli O157:H7, such as the elderly, young children, and those with compromised immune systems, not eat raw sprouts. Although FDA has provided guidance to sprout producers to enhance the safety of sprout products, these commodities are still causing problems.
Notably, FDA has been encouraged to mandate consumer warning labels for sprouts. These labels would warn high-risk consumers about the dangers of raw sprout consumption. While it requires similar warnings for other high-risk foods (such as unpasteurized juice and raw oysters), FDA has not moved forward to mandate sprout warnings.
10. BERRIES: 25 outbreaks involving 3397 reported cases of illness
In 1997, over 2.6 million pounds of contaminated strawberries were recalled after thousands of students across several states reported illnesses from eating frozen strawberries in their school lunches. Hepatitis A was the culprit, and contamination may have occurred through an infected worker at a farm in Baja California, Mexico. That same year, raspberries imported from Guatemala and Chile were implicated in an outbreak of Cyclospora across five states. Most of these illnesses, affecting 2700 consumers, were caused by Cyclospora in berries. The resulting infection is a parasitic illness of the intestines, which can cause severe diarrhea, dehydration, and stomach cramps. Importantly, the illness does not resolve itself without antibiotics, thus requiring a trip to the doctor.
What can consumers do to protect themselves from foodborne illness? Follow these precautions form the Centers for Disease Control and Prevention:
COOK meat, poultry and eggs thoroughly. Using a thermometer to measure the internal temperature of meat is a good way to be sure that it is cooked sufficiently to kill bacteria. For example, ground beef should be cooked to an internal temperature of 160F. Eggs should be cooked until the yolk is firm.
SEPARATE: Don’t cross-contaminate one food with another. Avoid cross-contaminating foods by washing hands, utensils, and cutting boards after they have been in contact with raw meat or poultry and before they touch another food. Put cooked meat on a clean platter, rather back on one that held the raw meat.
CHILL: Refrigerate leftovers promptly. Bacteria can grow quickly at room temperature, so refrigerate leftover foods if they are not going to be eaten within 4 hours. Large volumes of food will cool more quickly if they are divided into several shallow containers for refrigeration.
CLEAN: Wash produce. Rinse fresh fruits and vegetables in running tap water to remove visible dirt and grime. Remove and discard the outermost leaves of a head of lettuce or cabbage. Because bacteria can grow well on the cut surface of fruit or vegetable, be careful not to contaminate these foods while slicing them up on the cutting board, and avoid leaving cut produce at room temperature for many hours. Don’t be a source of foodborne illness yourself. Wash your hands with soap and water before preparing food. Avoid preparing food for others if you yourself have a diarrheal illness. Changing a baby’s diaper while preparing food is a bad idea that can easily spread illness.
REPORT: Report suspected foodborne illnesses to your local health department. The local public health department is an important part of the food safety system. Often calls from concerned citizens are how outbreaks are first detected. If a public health official contacts you to find our more about an illness you had, your cooperation is important. In public health investigations, it can be as important to talk to healthy people as to ill people. Your cooperation may be needed even if you are not ill.
Related: Top 12 Toxic Fruits and Vegetables