1.1.1: Causes of Foodborne Illnesses
Causes of Foodborne Illnesses
Foodborne illnesses can be caused by:
- Contaminants
- Improper food handling practices
- Food allergies
Understanding each of these is critical in ensuring that food safety is maintained. [1]
Food contaminants can be:
- Chemical, such as cleaning agents or pesticides
- Physical, such as hair, bandages, or glass
- Biological, such as pathogens and microbes introduced from infected workers, unsanitary work surfaces, or contaminated water
Biological causes of foodborne illness
Biological contaminants are by far the greatest cause of illness. Many of the risks associated with biological contaminants can be controlled or removed by effective food handling practices, so it is critical that the safe food handling and prevention procedures outline in the rest of the book be followed.
Microbes are all around us. They are living things, often too small to be seen without a microscope. Many microbes are beneficial, but some can cause illness or even death. These harmful microbes are called pathogens . Five types of microbes include bacteria, viruses, parasites, protozoa, and fungi (mold).
- Bacteria are present in many of the foods we eat and the body itself. Most bacteria are not harmful, some are even very beneficial to people, but some types of bacteria are pathogenic and can cause illness. Campylobacter, E.coli, Listeria, and Salmonella are examples of pathogenic bacteria. Foods that contain these bacteria must be handled correctly and cooked appropriately.
- Viruses frequently cause illness, and are found in food, but do not grow or multiply in food. Most foodborne illness caused by viruses happens because the person handling the food has transmitted to the virus to the food through improper food handling or poor sanitation. Hepatitis A and Norovirus are examples of viruses that are responsible for foodborne illness.
- Parasites live in or on animals and people cause illness when the food infected with the parasite is not cooked to a temperature high enough or frozen to a temperature cold enough to kill the parasite. Roundworms (found in raw fish) are examples of parasites found in food.
- Protozoa are single-celled animals that may be found in water. Use of water from unsafe sources can lead to illness. Giardia lamblia is an example of protozoa that may be found in water from rivers, lakes, streams and shallow wells. Food washed in water containing Giardia lamblia that is served without any further cooking (such as salad greens) can cause illness.
- Fungi grow on decaying organic matter. Many fungi are harmless or beneficial, but some, such as mold that grows on spoiled food, can be harmful and remain even after cutting or scraping the visible mold off the food.
Food Intoxication and Food Infection
Have you ever had the “24-hour flu”? Many people who think they have the 24-hour flu have had a foodborne illness caused by some type of pathogen. A rapid reaction is normally caused by a food intoxication. A slower reaction is normally caused by a food infection. Here’s how to tell the difference between the two:
- Food intoxication occurs when bacteria grow in food and produce a waste product called a toxin. When the food is eaten, the toxins are immediately introduced into the body, causing a rapid reaction. Example: Staphylococcus
- Food infection occurs when food contains living pathogens that grow in the human intestinal tract after the food is eaten. Because the bacteria continue to multiply in the body and cause infection, the reaction will be slower. Example: Salmonella
There is also toxin-mediated infection which occurs when a biological pathogens are introduced to the body and after entering the digestive tract begin to produce a toxin. The toxin is what is responsible for the many symptoms associated with foodborne illness. Example: E.coli
Common Causes of Foodborne Illness
Bacteria:
While there are hundreds of different strains of bacteria that can cause illness in humans the Centers for Disease Control and Prevention (CDC) recognizes the top 5 types bacteria to cause illness in the United States as:
| Hepatitis A | Campylobacter Jejuni | Clostridium perfringens | E.coli | Listeria | Salmonella | |
| Source |
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| Incubation Period | 28 days average (ranges from 15 to 50 days) | 2 to 5 days | 6 to 24 hours | 3 to 4 days for most people, can be 1 to 10 days |
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6 hours to 6 days |
| Symptoms |
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| Duration | Less than 2 months. Some people can be ill for as long as 6 months. | ~1 week |
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Days to weeks | 4 to 7 days |
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"Adapted from: https://www.fda.gov/food/consumers/w...orne-illnesses "
For more information on the above bacteria please visit the CDC website: here.
Viruses:
The majority of foodborne illnesses are caused by bacteria, however, there are several viruses that are common within the United States that can also cause illness. Examples of viruses are:
- Norovirus
- Hepatitis A
Please visit the link above to learn more about Norovirus.
For more information on Norovirus please watch the following video from the CDC: CDC Norovirus Prevention Video.
Improper Food Handling Practices
The top 10 causes of foodborne illness are the following:
- Improper cooling
- Advance preparation
- Infected person
- Inadequate reheating for hot holding
- Improper hot holding
- Contaminated raw food or ingredient
- Unsafe source
- Use of leftovers
- Cross-contamination
- Inadequate cooking
Food Allergies
Food allergies are specific to individuals, but can be life threatening, and can be prevented by a thorough understanding of the allergy issue, knowledge of ingredients used in the preparation of foods, including pre-prepared foods, and care in ensuring separate cooking utensils, cookware, and food preparation surfaces. Oftentimes, the smallest oversights can have serious consequences, as indicated in the example below:
A customer has indicated they have an allergy to shellfish and ordered chicken strips with a house dipping sauce. The server assures the customer that there will be no shellfish used in the preparation of what they ordered. After eating the meal, the customer experiences tingling lips and hives. In follow up, the manager discovers that the oil used to fry the chicken strips had also been used to fry shrimp.
This incident could have been prevented if cross contact was eliminated and different fryers were used to prepare menu items.
Allergic reactions occur when the body mistakenly reacts to a food that has been eaten as an intruder to the body. Allergens trigger the immune system whose job it is to eliminate harmful foreign bodies from circulation. This reaction results in an increase in white blood cells and the production of antibodies (Immunoglobulin E IgE). Allergic reactions can be experienced as mild symptoms such as a runny nose or itching, to more severe reactions such as anaphylaxis.
Anaphylaxis involves multiple organ system and can decrease an individuals blood pressure and affect their ability to breathe making this a life-threatening reaction.
Top Food Allergies:
There are currently 8 food allergens recognized in the United States that are responsible for 90% of all allergic reactions. In April of 2021, the Food Allergy Safety, Treatment, Education, and Research (FASTER) Act was signed into law by President Joe Biden making sesame the 9th major food allergen. Starting January 1, 2023 foods produced for sale in the United States will be required to identify food sources of sesame on the labels.
Top allergens:
- Peanuts
- Tree nuts
- Milk
- Soy
- Wheat
- Eggs
- Fish
- Shellfish
- Sesame
Source: https://www.fda.gov/food/food-labeli...nited%20States .