What is a Food Poisoning or Foodborne Illness Outbreak?

How Well Are They Detected, Reported and Investigated?

Definition

The U.S. Centers for Disease Control and Prevention defines a food poisoning or foodborne illness outbreak as two or more people who become ill, or die after eating the same food. Some state and local departments of public health may define it as more than two.

This definition goes beyond just two or more people who ate the same food at the same restaurant. It also includes the same food product that was purchased at any number of different markets or locations across the country, which in most cases leads to a recall of that product. In other words an outbreak can involve processed foods eaten at a restaurant, or raw or packaged foods purchased at a market and prepared/processed at your home or other commercial kitchen.

Outbreak Size Statistics

The majority of outbreaks are in the 2-5 people affected range, followed by 10-49 numbers of affected people. The 6-9 number of people affected, for some reason, is about half the number of outbreaks as the 10-49 people. And the greater than 50 people affected, although the fewest number of actual outbreaks, has the greatest number of people affected.

Here are those same numbers in a table format:

Source: Scripps Howard News Service's study of 6,374 reports received by the CDC from Jan. 1, 2000, through Dec. 31, 2004. http://www.scrippsnews.com/node/16838?page=6

 

Where is the Greatest Likelihood of an Outbreak Occurring?

The general belief is that most food poisonings occur from something gone wrong in your own home kitchen. This sounds sensible because the majority of meals are still prepared and / or eaten at home.

The reality though is quite a bit different, at least when looking at outbreak numbers. (For non-outbreak or what's called "sporadic" foodborne illness cases, read how their sources break down at Where is The Greatest Risk of Contracting Food Poisoning?) Restaurants are a slight majority with private residences a distant second. All the more reason why you, as a consumer, need to be more aware of the environment at a restaurant, including the establishments inspection history and especially its food poisoning history. To learn much more on this subject click on any of the following articles:

• Learn How to Identify the Signs of a Safe Restaurant
• Poor Personal Hygiene Practices in a Restaurant
• Obvious and Not So Obvious Signs of a Potential Food Poisoning Hazard Once the Food is at Your Table?
• Ways to Find Out More on Food Safety and Violations at Restaurants and Markets in Your Neighborhood!

Here are the outbreak numbers: 

Source: Scripps Howard News Service's study of 6,374 reports received by the CDC from Jan. 1, 2000, through Dec. 31, 2004. http://www.scrippsnews.com/node/16838?page=6

 

How is it Detected and Investigated – the Tricky Part

Unfortunately even with today's advanced diagnostic medical and microbiological technologies, the majority (approximately 64%) of outbreaks have an unknown cause (see below for breakdown of causes).

The investigation of an outbreak may stay entirely local or could be nation wide. An example of a local outbreak is where a specific restaurant or commercial kitchen or catered event is the source of the contaminated food. For an example of a nationwide outbreak one merely has to read and watch the news for what seems like a regular E. coli, Listeria or Salmonella outbreak involving a regional or nationwide store or product. These appear to be in the news at least once a month. A Salmonella outbreak is in fact at the time of this writing, plaguing the U.S. sickening thousands of people, the source of which are eggs from one particular farm Iowa.

“It is often difficult to identify sources of foodborne outbreaks. People may not remember the foods they recently ate and may not be aware of all of the ingredients in food,” said CDC spokesman David Daigle. “That’s what makes these types of investigations very difficult.”

As soon as an outbreak occurs, the public health department investigates. The first priority is to rush the affected individuals for treatment, depending on the severity of their symptoms. Next, investigate and identify the cause and take steps to prevent any future incidents. Here are some of the actions taken:

• As a result of the investigation, the authorities, including local state and sometimes federal, discern critical information like the source of the poisoning, which as already mentioned can be the most difficult part of the investigation. Several experts participate in the investigation including an epidemiologist, environmental health specialist, veterinarian, microbiologist, public health nurse and others.
• Try to identify how many more people might be at risk and how many have been affected.
• The demographics of these affected or infected people are studied and blood and stool samples are taken in an attempt to diagnose what the contaminant could be.
• After the contaminant is found, it is traced to the product or food that might have been the cause behind the food poisoning. For example, many people who consumed the same sauce might have fallen ill. The sauce may have been made using eggs that came from a farm where the chickens were harboring Salmonella.
• Action is now taken to prevent any further outbreaks.

The critical part is to make an accurate diagnosis of what could have caused the problem and to arrest it from continuing to infect people so that the outbreak can be stopped from spreading further. The contaminated product may then be recalled from the market. Sometimes, restaurants are closed down for further investigations. Past investigations also help in this regard since an association can be made between the symptoms of a food poisoning outbreak and a specific type of food item, making it easier to find the cause.

Outbreaks do make the news more than ever before and in many cases involve a product recall. Many recalls occur also without any reports of actual illness. The inspection and detection systems in place have improved in recent years in attempting to catch contaminated foods before they are able to cause illness, although still far from perfect or in some cases even good. The standards for food inspections, surveillance and reporting of food borne illnesses are still severely lacking, and in many U.S. states very poor.

Causes of Food Poisoning Outbreaks

Looking again at the statistical breakdown, you will see the large percentage (64%) of unknown causes compared to the known causes. Also, bacterial and viral causes are close in numbers while chemical and other causes fall to a small percentage. My guess is that most of the unknown (at least in the U.S. and other western or developed countries) are bacterial or viral in nature and that due to time delays in detection and other difficulties in getting samples and specimens, are just not identifiable. The other possibility is that there are still a number of microorganisms in the environment that we have yet to identify.  This is very possible when you consider some of the pathogenic microorganisms of great concern today (e.g., Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, Cyclospora cayetanensis) were not recognized as causes of food borne illness just 20 years ago.

The high percentage of unknown causes is alarming. It basically means that if the authorities are unable to determine the cause including the food and the actual disease element (bacterial, viral etc.) they are not able to prevent the outbreak from spreading or prevent another of similar origin from occurring.

What you should do if you believe you are part of an outbreak?

Immediately report it to your local public health department. I describe all the information you need and the process to follow at the following link:

How To Report Your Food Poisoning Illness to Your Local Public Health Department

Treatment

For an extensive list of natural treatments, remedies and other possible cures, click on the link and read my article at www.FoodPoisoningPrevention.com/Treatements_Remedies.htm