An outbreak of foodborne illness occurs when a group of people consume the same contaminated food and two or more of them come down with the same illness. It may be a group that ate a meal together somewhere, or it may be a group of people who do not know each other at all, but who all happened to buy and eat the same contaminated item from a grocery store or restaurant. For an outbreak to occur, something must have happened to contaminate a batch of food that was eaten by a the group of people. Often, a combination of events contributes to the outbreak. A contaminated food may be left out a room temperature for many hours, allowing the bacteria to multiply to high numbers, and then be insufficiently cooked to kill the bacteria.
More than 250 different food borne diseases have been identified to date – not inclusive of chemical agents. Most of these diseases are infections caused by a variety of bacteria, viruses, and parasites. Of course, foods that are contaminated with poisonous chemicals or harmful substances can also cause serious illness. Symptoms of food borne illness vary by disease but with bacterial or viral infections the most common are nausea, vomiting, abdominal cramps, and diarrhea – usually of unusual severity. Food poisoning with a toxic chemical will usually show severe symptoms very quickly, as will food allergies. Immediate medical attention is called for in each of these cases.
Incubation Periods of the Most Common Food borne Pathogens
1 to 8 hours, typically 2 to 4 hours.
2 to 7 days, typically 3 to 5 days.
E. coli O157:H7
1 to 10 days, typically 2 to 5 days.
6 to 72 hours, typically 18-36 hours.
12 hours to 7 days, typically 1-3 days.
15 to 50 days, typically 25-30 days.
3 to 70 days, typically 14 days.
24 to 72 hours, typically 36 hours.
Common myths of food borne illness
As you attempt to determine if you have a food borne illness and what the potential source could be, avoid these common misperceptions.
Not necessarily. Referring to the above incubation period table that shows how long it takes for certain microbes to grow inside your body and cause illness, you see this is not always the case. Write down what you ate, where you ate, and when you ate in as much detail as possible. Accurate recall of this information is critical.
Not necessarily. It is well documented that the microbes that cause food borne illness are not always uniformly distributed in a food item. Also, people have different immune systems. One person may consume hamburger prepared from a package of ground beef and become seriously ill with E. coli O157:H7 or Salmonella while his dining companion consumes ground beef from the same package and remains healthy. Different people react differently to different pathogens and toxins.
How can I find out if I am sick because of something I ate or drank?
Severe symptoms usually result in a trip to the emergency room or to a physician. Food borne infections are usually diagnosed by laboratory tests that identify the organism. Bacteria such as E. coli O157:H7, Salmonella, Shigella, and Campylobacter are found by microbiologic testing of the ill person’s stool. Parasites can be identified by examining stool specimens under the microscope. Laboratory testing to detect viruses requires stool specimens or serum derived from blood samples. Many food borne infections are not detected through routine laboratory procedures and health care providers must order appropriate testing before the cause can be identified. If you go to a hospital or see a physician and you suspect food poisoning, ask the doctor to test specifically for the more common pathogens.
Should I see a doctor if I think I have a food borne illness?
A person with symptoms of a food borne illness should seek prompt medical attention, especially if there is blood in the stools, if they are experiencing prolonged vomiting or show signs of dehydration, if diarrhea last 3 days or more or you notice unusual changes in your stool including increased mucus or an unusual dark color (especially if it is black, which is highly indicative of bleeding in the intestinal tract) especially black tarry stools. Anyone at risk for serious consequences – the very young, the very old, or those with immune impairment – should consult a health care provider if symptoms do not improve after 24 hours. In addition, those with severe symptoms regardless of their age or health should immediately go to the nearest emergency room or call 911. This can be especially critical if there are any signs of difficulty breathing, thready pulse, severe sweating, fever or swelling, dizziness or fainting. It is also important to eliminate any cardiovascular issues or the possibility of allergy with resulting anaphylactic shock – both of which are also life threatening.
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