food poisoning, foodborne illness, salmonella, salmonellosis, Dr. Dale Peterson, egg recall, spinach recall, campylobacter, Guillain-Barre, E. coli O157:H7, Calicivirus, Shigella, shigellosis, giardia, giardiasis, staph, staphylococcal, oysters, mushrooms, botulism

Foodborne Illness: A Rising Threat

Foodborne Illness: A Rising Threat

© 2010 Dale Peterson, M.D &

If you are like most people, you have had the experience of going to bed feeling perfectly fine, but awakening in the middle of the night with intense nausea and vomiting. Soon you begin to experience severe abdominal cramping, which is followed by diarrhea. Body aches, headaches, and fever may accompany the upset stomach.

You may have contracted a stomach virus, but it is just as likely that you were a victim of what is referred to as food poisoning. A more accurate term is foodborne illness, and it is being seen with increasing frequency, and in larger numbers of people. In August 2010 a nationwide outbreak of salmonella food poisoning resulted in the recall of over 500,000,000 eggs. It was not the first food recall of the year, nor would it be the last.

Approximately 1.2 million pounds of salami and other ready-to-eat sausages were recalled in January. In March over fifty different processed foods including soups, snack foods, dips and dressings were recalled when salmonella were found in hydrolyzed vegetable protein (HVP), one of the flavoring agents used in the manufacturing of the products. In October over 1,000 cantaloupes distributed by Del Monte were recalled. Outbreaks of foodborne illness triggering smaller recalls occurred regularly throughout the year.

While eggs received the most notice, the foods carrying disease-causing organisms were extremely diverse. Chopped celery, Subway sandwiches, peanuts and peanut butter, Taco Bell fast foods, barbecued pork, fruit compote, ice cream, salad dressing, potato chips, and a host of other foods were implicated. It is clear that no food can be declared safe in today’s society.

It is estimated that 76 million cases of foodborne illness occur in the United States each year. Food poisoning is responsible for 325,000 hospitalizations and 5,000 deaths. The economic cost is estimated to be $152 billion annually, an average of $1,850 for each person who is affected.

Over 250 different foodborne diseases have been identified. Most are infections caused by viruses, bacteria, and other microorganisms. Some are due to chemical contamination, and others are caused by toxins such botulinum or those found in poisonous mushrooms.

The most commonly recognized bacterial foodborne infections are caused by campylobacter, salmonella, and E. coli 0157:H7. Calicivirus is responsible for many cases of foodborne illness, but since there is no readily available laboratory test, it is rarely identified.

Campylobacter infections are characterized by fever, diarrhea that may be bloody, and abdominal cramping. Campylobacter are identified as the cause of diarrhea more often than any other bacteria. The bacteria live in the intestines of healthy birds, and they are therefore present on most raw poultry. Eating undercooked chicken or uncooked food that has been contaminated by drippings from raw chicken is the most common cause of campylobacter infections.

It is often difficult to identify the source of campylobacter because the infection may not be evident for up to ten days after the offending food has been eaten. The typical delay from exposure to onset of symptoms is 2 – 5 days. Most cases are mild, but a campylobacter infection can be fatal in someone with a compromised immune system. The illness should resolve within a week, but may persist for up to three weeks. Relapses are common. Approximately 1 person in 1,000 will develop a condition called Guillain-Barre syndrome (GBS). GBS is a condition in which the body’s immune system creates antibodies that mistakenly attack the sheaths that insulate the body’s nerve cells. This occurs because the sheaths are chemically similar to certain bacterial components. Sheath damage slows or interrupts the transmission of nerve signals to muscles, which results in weakness or paralysis. Most people recover from GBS, but breathing may need to be supported by a respirator for a time and full recovery may take several years.

Individuals who carry a genetically determined antigen called HLA-B27 may develop arthritis in the knees and hips following a campylobacter infection. The bacteria can also infect the appendix, gallbladder, heart, urinary tract, and blood or cause meningitis.

Salmonella is a bacterium that is commonly found in the intestines of birds, reptiles and mammals. Pet turtles can be a source of infection, as can turtles found in the wild. Thorough hand washing after handling a turtle should prevent infection.

One of the unique characteristics of the salmonella organism is its ability to infect the ovaries of birds. It is then incorporated into eggs as they are laid. The salmonella outbreak of 2010 occurred because chickens fed salmonella containing bone meal subsequently laid eggs that contained the bacteria. Humans became ill after eating the adulterated eggs.

Salmonellosis, the disease caused by salmonella bacteria, typically presents with fever, diarrhea, and abdominal cramping. The illness generally passes within 24 – 48 hours in healthy individuals, but may be prolonged in others. Approximately 1,000 deaths from salmonellosis occur in the United States annually.

A particular strain called salmonella typhi causes a more serious illness, typhoid fever. Unlike other strains, salmonella typhi is carried only by humans. Food handlers, who may be asymptomatic, can pass the bacteria to others. The most famous was Mary Mallon, a cook in Oyster Bay, New York who in 1906 spread the disease to 53 individuals, five of whom died. She is remembered as “Typhoid Mary”. After the outbreak was traced to her she was placed in quarantine for a time, but released under the condition that she would not work as a cook. In 1915, however, twenty cases of typhoid fever at Sloan Hospital for Women were traced to a cook named “Mary Brown”, who was actually Mary Mallon.

The third bacterial cause of foodborne illness is E. coli O157:H7, a disease-causing strain of a normally benign bacterium that is commonly found in the human intestinal tract. Cattle are its chief reservoir. Human illness occurs when food or water that has been contaminated with microscopic amounts of cattle feces is consumed. E. coli O157:H7 was responsible for the spinach scare of 2006 and is the most common cause of foodborne illness related to the intake of fresh produce. Over 400 outbreaks have been reported in the United States since 1990.

When fields of growing produce are irrigated with water contaminated with the bacteria it is taken up by the roots and incorporated into the plant itself. Therefore washing the leaves of a plant such as spinach before eating it will not prevent infection.

E. coli O157:H7 causes bloody diarrhea that is often severe. Painful cramping occurs, but a significant fever is rare. In up to 5 percent of cases a severe complication called hemolytic uremic syndrome (HUS) occurs. HUS can cause anemia, extensive bleeding, kidney failure, and death.

Calicivirus infections are the most common viral cause of foodborne illness. Since laboratory testing for the virus is not readily available it is rarely diagnosed. Calicivirus infections are more likely to cause vomiting than diarrhea. The illness comes on suddenly and generally resolves within 48 hours. It is believed that the virus spreads from one infected person to another by direct hand-to-hand contact or by contamination of food by persons who have the virus on their hands. Kitchen workers can contaminate a salad and infected fishermen have been reported to contaminate oysters as they harvest them.

Oysters can also cause illness if they contain Vibrio bacteria, which are naturally present in sea water. Infection is most likely to occur when water temperatures are above 40 degrees Fahrenheit, so it is recommended that raw oysters not be eaten from April through October. I would not recommend eating them at any time of the year, as they can also carry the hepatitis A virus, which is unaffected by water temperature.

A number of other diseases are occasionally foodborne, although they are generally contracted in other ways. These are shigellosis, hepatitis A, giardiasis, cryptosporididosis, and staphylococcal poisoning.

Shigelosis is caused by members of the shigella family of bacteria. Diarrhea, which is often bloody, develops within a day or two of exposure. The illness generally resolves within a week, but it may take several months for bowel movements to return to normal. Antibiotics are indicated only in severe or persistent infections. Spread is typically person-to-person, but it can occur if food prepared by a person with contaminated hands is eaten.

Hepatitis A is also typically spread by person-to-person contact, but it can also be spread by contaminated food. I dealt with several foodborne outbreaks of hepatitis A in the 1970s and 1980s prior to the availability of the hepatitis A vaccine. While the people I saw in my practice were rarely concerned about contracting hepatitis A unless they were going to Mexico, they were actually at greater risk of becoming ill at home. At that time Oklahoma City had the highest rate of hepatitis A infections in the United States; this was almost certainly due to the city’s dubious distinction of having the highest percentage of people eating out in the country.

Giardia lamblia is a protozoan that is commonly found in the intestinal tracts of beavers. It typically presents in people who have been hiking or camping and have drunk untreated water from what appeared to be a pure and refreshing mountain stream, but I have occasionally seen cases in which it was contracted from fresh produce. Giardiasis is characterized by profuse and prolonged diarrhea. Gassiness and bloating are common, and abdominal pain may also occur. Antibiotic treatment is often required to clear the infection.

Cryptosporidia are parasites that have a protective coating called an oocyst. This allows them to survive in the environment for extended amounts of time. Unlike most germs that cause disease, cryptosporidia is not easily killed by methods used for water purification. Therefore outbreaks can occur in communities in which the tap water is contaminated. Food can be contaminated by being washed in contaminated water or if handled by an individuals with cryptosporidia on their hands. Cryptosporidosis causes nausea and watery diarrhea. Symptoms begin within ten days of swallowing the oocysts. They normally resolve within two weeks, but oocysts can continue to be shed in the stool for up to two months.

Staphylococcus aureus is most commonly associated with skin infections such as impetigo, but the bacteria can also grow in foods. When food is contaminated by staph aureus, a toxin that causes intense vomiting along with diarrhea and abdominal pain is produced. Because symptoms are caused by the toxin rather than by germs that need time to multiply, the onset of staphylococcal food poisoning is very rapid. Vomiting can begin in as little as 30 minutes from the time the food is ingested, and symptoms almost always present within six hours of exposure. The illness generally resolves within 24 – 72 hours without treatment.

Botulism is another form of toxic food poisoning. The causative agent is Clostridium botulinum. The toxin causes a progressive paralysis that is often fatal. The most common source is home-canned food that was not adequately sterilized and sealed. The first case of botulism I saw as an intern was traced to a home-canned jar of okra.

Some species of mushrooms contain toxic substances. The primary cause of mushroom poisoning is an inability to distinguish poisonous from safe species when gathering wild mushrooms.

Foodborne illness is not a new phenomenon. What has changed is the scale at which it is being seen. In years past outbreaks were generally limited to small numbers of people who had eaten contaminated food at a single location. The exposure may have occurred at home, at a community gathering, or at a local restaurant. Today it is not uncommon for hundreds or even thousands of people to be exposed simultaneously in multiple locations. The 2010 egg-related outbreak involved eggs sold under nearly twenty different brand names in approximately fifteen states. The 2006 spinach outbreak involved packages of organic spinach that had been distributed to 26 states.

In years past, when food was predominantly grown on family farms, outbreaks were less common and much more limited in scope. Today foods are derived primarily from large corporate producers where contamination can involve massive numbers of plant or animal products.

The challenge is intensified by the practice of mixing food from multiple sources in a product. In order to standardize size and shape, hamburgers sold at fast food chains are prepared by blending the meat from many cattle. A single hamburger may contain meat from over 100, or even 1,000 different cattle. If the meat from a single steer was contaminated during processing hundreds of people may be exposed. Since restaurants commonly premix eggs for omelets, a single omelet may contain eggs from hundreds of chickens.

Given the extent of foodborne illness it is important that people take steps to protect themselves from it. Little to nothing can be done to prevent food poisoning when eating away from home, so one of the best strategies that can be used is to eat in more often. When eating out, wash your hands or use a hand disinfectant to remove disease-causing organisms with which you may have come into contact before eating. Choose foods that are “well-done” as the cooking process will kill most disease-causing organisms.

When eating at home follow what I call “The Five Cs”. They are:

Clean: 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. Wash your hands with soap and water before preparing food. Avoid preparing food for others if you yourself have a diarrheal illness.

Contain: 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.

Cook: Microbes are killed by heat. Heating the food to an internal temperature above 160 degrees Fahrenheit for even a few seconds is sufficient to kill parasites, viruses or bacteria, except for the Clostridium bacteria, which produce a heat-resistant form called a spore. Clostridium spores are killed only at temperatures above boiling. This is why canned foods must be cooked to a high temperature under pressure as part of the canning process. The toxins produced by bacteria vary in their sensitivity to heat. The staphylococcal toxin which causes vomiting is not inactivated even if it is boiled. Fortunately, the potent toxin that causes botulism is completely inactivated by boiling.

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. One bacterium that reproduces by dividing itself every half hour can produce 17 million progeny in 12 hours, so lightly contaminated food left out overnight can be highly infectious by the next day. Divide large quantities into several shallow containers for refrigeration, as this will allow it to cool completely more quickly.

Colonize: Use probiotic supplements periodically to promote a strong growth of protective organisms in the intestinal tract. The presence of supportive bacteria in the intestinal tract is the best defense against foodborne illness. When normal flora are present, disease-causing organisms will find it more difficult to multiply sufficiently to cause illness and the condition will be less severe and of shorter duration if it does occur.

If you suspect that you have developed food poisoning immediately put your stomach and intestines to rest. Limit your intake to sips of water until vomiting stops and consume nothing but clear liquids until the diarrhea slows. It is extremely important to avoid anti-diarrheal medications such as Immodium AD, as they will prevent your body from eliminating the offending organism and prolong or intensify the illness. Pepto Bismol may be used, and psyllium husk may be helpful in restoring formed stools.

If dehydration, characterized by a decrease in urination, a dry mouth, or feeling dizzy when standing up develops it can be treated successfully in nearly all instances by preparing a rehydration solution from common ingredients. The recipe is 1 quart of water, ¾ tsp. salt, 1 tsp. baking soda, 1 cup orange juice, and 1 – 2 tablespoons of an unrefined sweetener such as barley malt, brown rice syrup, dried cane juice, honey (do not use honey in infants less than a year of age), maple syrup, molasses, sorghum, or Sucanat.

Seek medical attention if you experience an oral temperature over 101.5 F, bloody stools, prolonged vomiting, or diarrhea that lasts more than 3 days.

Foodborne illness will always be a real and present threat. It is impossible to avoid all foods that could contain microbes or toxins. It is possible, however, to decrease your chances of becoming ill and to minimize its effect should an attack occur.

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