Foodborne Illness

Foodborne illness is a broad term that describes any sickness resulting from spoiled or contaminated food. It is so broad that the Centers for Disease Control and Prevention (CDC) reports that foodborne illness – also known as food poisoning and foodborne disease – includes:

  • more than 250 diseases
  • affects an estimated 48 million Americans each year
  • hospitalizes 128,000 victims
  • results in 3,000 deaths.

How does foodborne illness occur?

Food can become contaminated at any point during its journey from farm to table – from the very first stages of production, to processing in a plant, as well as at the distribution and preparation stages.

There are numerous ways for food to become contaminated:

  • Spoiling: describes spoilage as “any disagreeable change in a food’s normal state.” This can become apparent in a foul smell, a disagreeable taste (for example, sour milk), a change in texture, or an unnatural appearance (such as mold). Spoiled food can be caused by prolonged exposure to air, moisture and light, as well as being stored at incorrect temperatures – conditions that foster the production of bacteria and yeasts that speed the decomposition process.
  • Bacteria: Many different types of bacteria can cause food poisoning, but the most common are Salmonella, Escherichia coli (E. coli), Listeria monocytogenes (Listeria), Shigella, Campylobacter, and Clostridium perfringens. Bacteria break down food and produce acids and waste products that result in unhealthy and inedible food. (For tips on avoiding bacteria when cooking at home, see below.)
  • Viruses: A group of viruses called norovirus is the most common cause of viral food poisoning. Less common are rotavirus, which primarily affects young children, and adenovirus, which is best known for causing the common cold but can also result in gastroenteritis.
  • Parasites: According to, the most common parasites that cause food poisoning in the United States are protozoa, roundworms, and tapeworms.
  • Chemicals: Pesticides used to protect crops can result in illness when foods – primarily vegetables and fruit – are improperly cleaned.
  • Natural toxins: The incidence of food illnesses produced by natural toxins is very small, and is most commonly produced by some types of mushrooms and animals (for example, pufferfish).

Symptoms are numerous

The incubation period – the time between the consumption of contaminated food to the appearance of symptoms – can be anywhere from hours to days to even months, and depends on the agent. For instance, Bacillus cereus can produce symptoms in as few as six hours, while Listeria monocytogenes (Listeriosis) can take up to two months before it presents.

Symptoms, too, are numerous and can vary depending on the source of contamination. The most common symptoms are:

  • nausea and indigestion
  • vomiting
  • loss of appetite
  • diarrhea
  • bloating and gas
  • abdominal pain and cramps
  • fever
  • headaches
  • muscle aches.

If symptoms worsen, they can include:

  • fever
  • chills and sweating
  • fatigue
  • dehydration.

Anyone is susceptible to a foodborne illness, but those with the highest risk include the elderly, pregnant women, young children, and people with weakened immune systems (such as those with cancer, diabetes, HIV/AIDS, kidney disease, and transplant patients).

Avoiding bacteria at home

Bacteria multiply rapidly between 40 degrees and 140 degrees Fahrenheit. To ensure that food stays out of what the U.S. Department of Agriculture calls the “danger zone,” it’s important to keep cold food cold and hot food hot:

  • Store food in the refrigerator (40 degrees or below) or freezer (below 0 degrees).
  • Cook food to a safe minimum internal temperature, and use a food thermometer. Cook all raw beef, pork, lamb and veal steaks, chops, and roasts to a minimum internal temperature of 145 degrees, and then allow meat to rest for at least three minutes. Cook all raw ground beef, pork, lamb, and veal to an internal temperature of 160 degrees. Cook all poultry to a minimum internal temperature of 165 degrees.
  • Maintain hot cooked food at 140 degrees or higher.
  • When reheating cooked food, reheat to 165 degrees or higher.