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To anyone that has kept up with the news the fact that our food supply has faced jeopardy repeatedly over the past several years. Currently eggs are being recalled at an alarming and record rate from two Iowa producers with histories of contamination issues in egg production as well as poultry and swine production. Fruits and vegetables have been contaminated numerous times in the last two years and the list continues. It brings to question what is and isn’t safe in today’s commodity driven, regulated but not enforced food supply.
Salmonella (currently the most common contaminant) is a rather easy pathogen to deal with and is killed with proper cooking methods. Listeria, on the other hand, is potentially lethal to the very young and the very old and is a contaminant on pre-cooked meats in ready-to-eat sandwiches and deli meats.
According to the Center For Disease Control, The most commonly recognized foodborne infections are those caused by the bacteria Campylobacter, Salmonella, and E. coli O157:H7, and by a group of viruses called calicivirus, also known as the Norwalk and Norwalk-like viruses.
Campylobacter is a bacterial pathogen that causes fever, diarrhea, and abdominal cramps. It is the most commonly identified bacterial cause of diarrheal illness in the world. These bacteria live in the intestines of healthy birds, and most raw poultry meat has Campylobacter on it. Eating undercooked chicken or other food that has been contaminated with juices dripping from raw chicken is the most frequent source of this infection.
Salmonella is also a bacterium that is widespread in the intestines of birds, reptiles and mammals. It can spread to humans via a variety of different foods of animal origin. The illness it causes, salmonellosis, typically includes fever, diarrhea and abdominal cramps. In persons with poor underlying health or weakened immune systems, it can invade the bloodstream and cause life-threatening infections.
E. coli O157:H7 is a bacterial pathogen that has a reservoir in cattle and other similar animals. Human illness typically follows consumption of food or water that has been contaminated with microscopic amounts of cow feces. The illness it causes is often a severe and bloody diarrhea and painful abdominal cramps, without much fever. In 3% to 5% of cases, a complication called hemolytic uremic syndrome (HUS) can occur several weeks after the initial symptoms. This severe complication includes temporary anemia, profuse bleeding, and kidney failure.
Calicivirus or Norwalk-like virus is an extremely common cause of foodborne illness, though it is rarely diagnosed, because the laboratory test is not widely available. It causes an acute gastrointestinal illness, usually with more vomiting than diarrhea that resolves within two days. Unlike many foodborne pathogens that have animal reservoirs, it is believed that Norwalk-like viruses spread primarily from one infected person to another. Infected kitchen workers can contaminate a salad or sandwich as they prepare it, if they have the virus on their hands. Infected fishermen have contaminated oysters as they harvested them.
Some common diseases are occasionally foodborne, even though they are usually transmitted by other routes. These include infections caused by Shigella, hepatitis A, and the parasites Giardia lamblia and Cryptosporidia. Even strep throats have been transmitted occasionally through food.
In addition to disease caused by direct infection, some foodborne diseases are caused by the presence of a toxin in the food that was produced by a microbe in the food. For example, the bacterium Staphylococcus aureus can grow in some foods and produce a toxin that causes intense vomiting. The rare but deadly disease botulism occurs when the bacterium Clostridium botulinum grows and produces a powerful paralytic toxin in foods. These toxins can produce illness even if the microbes that produced them are no longer there.
This does not include contamination from pesticides, chemicals used in the maintenance of the processing and packaging equipment, accidental contamination during processing or the contamination by contact with a sick production worker. A century ago, typhoid fever, tuberculosis and cholera were common foodborne diseases.
Today other foodborne infections have taken their place, including some that have only recently been discovered. For example, in 1996, the parasite Cyclospora suddenly appeared as a cause of diarrheal illness related to Guatemalan raspberries. These berries had just started to be grown commercially in Guatemala, and somehow became contaminated in the field there with this unusual parasite. In 1998, a new strain of the bacterium Vibrio parahemolyticus contaminated oyster beds in Galveston Bay and caused an epidemic of diarrheal illness in persons eating the oysters raw. The affected oyster beds were near the shipping lanes, which suggested that the bacterium arrived in the ballast water of freighters and tankers coming into the harbor from distant ports.
In the last 15 years, several important diseases of unknown cause have turned out to be complications of foodborne infections. For example, we now know that the Guillain-Barre syndrome can be caused by Campylobacter infection, and that the most common cause of acute kidney failure in children, hemolytic uremic syndrome, is caused by infection with E. coli O157:H7 and related bacteria.
38.6 million reported cases of foodborne illness in the United States alone in five years (1992 – 1997). What’s more frightening then the raw numbers is the fact that it will get worse before it gets better.
What do we do to protect ourselves and our families? We obviously can’t stop eating and some of the pathogens are remarkably resistant to heat (during cooking) and antibiotics. The short answer is to buy locally, when possible, from known, trusted sources. Develop a relationship with a grocer that is careful not to intentionally sell contaminated foodstuffs. This unfortunately rules out most regional and national chain stores.
Many of us can raise our own fruits and vegetables and have local sources for meat and dairy. Others, however, have no such luxuries and for them the co-op and barter system should be considered. As some foods will be consumed regardless of risk, safe and healthy preparation practices will minimize the possibility of exposure.
In further articles we will look at more specific ways to safeguard the food we eat, our families and our pets without breaking the bank.
Data derived from the Center for Disease Control and the U.S.D.A.
