FOODBORNE ILLNESSES

 Foodborne illnesses are caused by organisms or harmful chemicals in the food we eat and drink. Most of these illnesses are caused when certain bacteria, viruses or parasites contaminate food. Others occur when food is contaminated by harmful chemicals or toxins. Over 250 different foodborne diseases have been described. It's not surprising that since most of these infections or chemicals enter the body through the stomach and intestines, the most common symptoms are nausea, vomiting, diarrhea and abdominal discomfort.

COMMON TYPES OF FOOD ILLNESSES

Around a hundred years ago, typhoid fever, tuberculosis and cholera were some of the most common diseases caused by bacteria contaminating food and water. Improvements in food processing and water treatment have almost eliminated these problems in the United States at the present time. Today, other bacteria and viruses have become common causes of foodborne disease, including Campylobacter, Salmonella, E. coli O157:H7, Shigella, Clostridium botulinium, Hepatitis A and Calciviruses. Bacteria called Vibrio parahemolyticus and a parasite called Cyclosporine have been found to be the cause of a few recent outbreaks of food borne illnesses.

Campylobacter

Campylobacter is the most common bacteria causing food borne diarrhea in the world. These bacteria live in the intestines of birds, and can often contaminate raw poultry such as chicken. Eating undercooked chicken, or eating food contaminated by juices from raw chicken are common ways of contracting this illness. Diarrhea that is often bloody, abdominal cramps and fever are common symptoms. Most people recover from Campylobacter diarrhea with no special treatment. The illness can also be treated with antibiotics such as erythromycin, ciprofloxacin or azithromycin. Rarely, patients can develop arthritis after an infection with Campylobacter. A small number of people develop a type of paralysis called Guillain-Barre' syndrome 2-4 weeks after recovering from Campylobacter infection.

Escherichia coli O157:H7

Escherichia coli (E. coli) bacteria are normally found in everyone's colon, and most types of E coli cause no problems at all. Certain types of E. coli can however cause serious illness, most commonly diarrhea. E. coli O157:H7 is a certain type of E. coli that lives in the intestines of mammals such as cattle. Humans become ill when they eat food contaminated by feces of animals infected with this organism. Hamburger meat seems to be a common source, as the grinding process allows organisms that were only on the surface of meat to be mixed throughout. Also, one infected cow can contaminate a large amount of hamburger as meat from many cattle is often mixed together. Outbreaks of E. coli O157:H7 have also been cause by eating contaminated salami, lettuce and alfalfa sprouts, or drinking unpasteurized milk and apple juice, and contaminated well water.

E. coli O157:H7 can cause severe and bloody diarrhea with painful abdominal cramps. Most people recover without problems in 5 to 10 days. Antibiotics are not particularly helpful. Less than one in twenty patients, most commonly children, can develop a severe complication with low blood count, bleeding, and kidney failure, called hemolytic uremic syndrome.

Enterotoxigenic E. coli is another type of E. coli that can cause severe watery diarrhea. It is very common in developing countries, where it's often spread on unwashed fruits and vegetables, and in drinking water. It is probably responsible for the majority of traveler's diarrhea, and is very likely the leading cause of childhood diarrhea in developing countries.

Salmonella

Salmonella is a bacterium found in the intestines of birds, reptiles and mammals. It can be spread through eating raw poultry, eggs, meat, and unwashed fruit. A person with this infection usually develops fever, diarrhea and abdominal cramps. Most people get better on their own, and do not need medication. Some sicker patients require antibiotics, intravenous fluids and hospital admission. In people with weakened immune systems, salmonella can get into the bloodstream and cause severe illness and even death. Occasionally, people recovering from salmonella infection can develop irritated eyes, painful joints and pain with urination, a condition called Reiter's syndrome. Some people infected with salmonella can have no symptoms at all, but become chronic carriers who can spread disease to others. "Typhoid Mary" Mallon, for example, was a cook in the early 1900's, who was never sick with salmonella, but had salmonella bacteria in her stool. Over the course of many years, many people she cooked for became ill, probably from bacteria passed to food from her hands.

Shigellosis

Shigellosis, also known as bacillary dysentery, is caused by Shigella bacteria. It is also spread through eating contaminated food and drink. Persons with this infection develop fever, bloody diarrhea, and abdominal pain. Although patients can usually recover without any specific treatment, many patients are treated with antibiotics once they are diagnosed.

Botulism

Botulism is a disorder caused by a toxic chemical produced by a bacterium called Clostridium botulinum. This bacterium grows best in sealed containers such as cans that have not been heated enough to kill the botulinium spores. The bacteria grow best where there is little or no oxygen. It produces a toxin that can cause paralysis, breathing failure, and even death. Patients ingesting this toxin can develop double vision, drooping eyelids, slurred speech, difficulty swallowing, and difficulty breathing.

FOODS MOST LIKELY TO CARRY DISEASES

Uncooked meat, raw eggs, and unpasteurized milk are the most likely foods to be contaminated. Foods such as ground beef, pooled raw eggs or unpasteurized milk, which are prepared by combining sources from many different animals, are especially problematic, as a whole batch can be contaminated by one infected animal. Vegetables that are eaten raw are also a problem, as they can be contaminated by washing with impure water or by fertilization with manure from infected animals. Raw shellfish are easily contaminated by sewage because these animals are filter feeders that feed by straining large quantities of seawater.

Even properly prepared food can be cross contaminated when juices from raw foods are dripped onto cooked food or when utensils or cutting boards used for raw food are also used for cooked food.

Information: American College of Gastroenterology; James A. Butler; Dr. Greg Martin.