Saturday, May 11, 2013

Dangerous Food - The Causes


Although the food supply in the United States remains one of the safest in the world, the CDC, Centers for Disease Control estimates that every year more than 300,000 Americans are hospitalized, and 5,000 die from foodborne illness. Preventing foodborne illness and death remains a major public health challenge.

A foodborne illness is any illness caused by the ingestion of food. Although the term food poisoning is frequently used, most foodborne illnesses are not in fact the result of toxins, chemicals or poisons created by the food itself, but are caused by one of several kinds of microorganisms present in the food. The commonest causes of food borne illnesses are bacteria, including Salmonella, E.coli, Listeria, and Shigella. Some bacteria secrete toxins as they grow; for example the Clostridium bacteria secretes botulin toxin, which can be fatal.

An estimated 55% of foodborne illnesses are caused by improper cooking and storage of foods, and 24% by poor hygiene, especially the failure to wash hands before handling food. Only 3% of cases are from an unsafe food source.

In a foodborne illness, symptoms may start within hours of eating the food, or they be delayed as much as three days. Symptoms vary with different microorganisms, and can include one or more of these: nausea, abdominal pain, vomiting, diarrhea, gastroenteritis, fever, headache or fatigue. Babies and small children, pregnant women and their fetuses, the elderly, people who are chronically ill, and others whose immune systems are compromised are at greatest risk.. In most cases there is a period of acute illness, then a recovery as the body rids itself of the toxic agent.

Escherichia coli, or E. coli for short, is a common bacterium found widely in soil, and normally in human and animal intestinal tracts. There are hundreds of different varieties of E. coli, most which are harmless, but some varieties can cause serious illness. Certain strains of E. coli can cause severe diarrhea and also infect the genital and urinary tracts.

In September 2006 a widespread outbreak of E. coli infection in raw spinach led to over 205 confirmed illnesses and three deaths across the country. The U.S. Food and Drug Administration warned consumers not to buy or eat raw spinach from any source. California's Department of Health Services and the US Food and Drug Administration worked cooperatively in the investigation. In their joint final report they successfully identified the environmental risk factors and the areas that were most likely involved in the outbreak, but they were unable to definitely determine how the contamination occurred.

The E. coli involved in the contaminated spinach is E. coli 0157:H7 http://www.medicinenet.com/script/main/art.asp?articlekey=2039 This variety was first identified in 1982, when it was found to be the causal agent in an outbreak of diarrhea resulting from the eating of undercooked beef. E. coli 0157:H7 produces toxins that damage the lining of the intestines. The result is severe, bloody diarrhea. Vomiting, abdominal cramps, and fever may also be present. The Centers for Disease Control estimates that this E. coli strain is responsible for an average of 73,000 cases of infection and 61 deaths each year in the US.

In 2007, several recalls of ground beef products have occurred, in which the beef was contaminated with E. coli. A restaurant in Effingham, Illinois, was identified as the source of an E. coli outbreak that resulted in at least six confirmed cases of E. coli O157:H7 among customers in September 2007. An outbreak also occurred among students at an Indiana elementary school.

More than half of US foodborne illnesses are viral. Most foodborne viral infections have an incubation period of 1-3 days before the victim experiences symptoms. The symptoms are similar to those listed for bacterial infections. In healthy individuals, a foodborne viral illness is self-limiting; as the body rids itself of the infected food and the viral particles, the symptoms abate.

Some foodborne illnesses have more far-reaching effects, causing long-term health problems or even death. Foodborne illness is a major cause of reactive arthritis, a painful inflammation of the joints or other tissues. Its onset is 1-3 weeks after the initial event, and it may persist for up to a year.

Other infectious agents in food include mycotoxins, produced by such fungal agents as Aspergillum, found in tree nuts, peanuts, and corn and cottonseeds; Ergot, which infects grains, and Fusarium, which infects corn, are all fungal toxins. There is still much to be learned about foodborne illness. For about sixty percent of all outbreaks of foodborne illnesses the source of the infection cannot be identified.

In addition to individual illness and suffering, food contamination and the resulting illnesses impose significant economic and social strains. In the U.S., medical costs and lost productivity caused by food borne diseases cost more than $35 billion annually.

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