By Flora McCraith, MSN, Updated: 2/11/2010

Foodborne illnesses

According to public health and food safety experts, each year, millions of people suffer from illnesses that can be traced to foodborne bacteria.

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The global occurrence of foodborne disease is hard to estimate, but it has been reported that in 2005 alone, 1.8 million people died from diarrhoeal diseases. A huge quantity of these cases can be credited to contamination of food and drinking water. Foodborne illness usually arises from improper handling, preparation, or food storage. The delay between consumption of a contaminated food and appearance of the first symptoms of illness is called the incubation period. This ranges from hours to days, depending on what bacteria was eaten and how much.

We look at the most common illnesses that can be caught through food and how to prevent catching them.

E.Coli

This is a bacterial pathogen that resides in cattle and other similar animals. Human illness usually happens after eating or drinking food or water that has been contaminated with microscopic amounts of cow faeces. The illness it causes is often severe, like bloody diarrhoea and painful abdominal cramps, without much fever.

Although their incidence is relatively low, their severe and sometimes fatal health consequences, particularly among infants, children and the elderly, make them among the most serious foodborne infections.

Salmonella

Salmonella is a major problem in most countries and it is caused by a bacteria which can be found in the intestine of birds, reptiles and mammals and can spread to humans through a variety of different foods.

Symptoms include fever, headache, nausea, vomiting, abdominal pain and diarrhoea. For people with general poor health or weakened immune systems, it can invade the bloodstream and cause life-threatening infections.

Listeria

Listeria is a type of bacterium often found in food and elsewhere in nature. It can cause a rare but serious disease called listeriosis, especially among pregnant women, the elderly or individuals with a weakened immune system. In serious cases, it can lead to brain infection and even death.

It is found in soil and water. Vegetables can become contaminated from the soil or from manure used as fertilizer. Animals can carry the bacterium without appearing ill and can contaminate foods of animal origin such as meats and dairy products. It has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing, such as soft cheeses and cold cuts at the deli counter.

Campylobacter

This is a bacterial pathogen that causes fever, diarrhoea, and abdominal cramps and is the most commonly identified bacterial cause of diarrheal illness in the world. Most people who become ill with campylobacteriosis get diarrhoea, cramping, abdominal pain, and fever within two to five days after exposure to the organism.

Eating undercooked chicken or other food that has been contaminated with juices dripping from raw chicken is the most frequent source of this infection. It is usually an isolated case rather than due to an outbreak.

Calicivirus

Calicivirus (Norwalk virus) is an extremely common cause of foodborne illness, though it is rarely diagnosed, because the laboratory test is not widely available. Norwalk viruses are spread by exposure to infected people or contaminated food and water and passed in stool and vomit. Outbreaks have been linked to sick food handlers, contaminated shellfish or water contaminated with sewage. It is generally spread from person to person by direct contact, but some medical reports suggest that the virus can spread through the air during vomiting.

Although the virus is easy to spread, serious illness rarely occurs. The most common symptoms include nausea, vomiting, and stomach cramps. Diarrhea may occasionally accompany vomiting. Fever is usually low grade or absent. Infected people generally recover in one to two days.

Cholera

Cholera is a big public health problem in developing countries. It has a short incubation period, from less than one day to five days, and produces an enterotoxin that causes copious, painless, watery diarrhoea that can quickly lead to severe dehydration and death if treatment is not promptly given.

Water and contaminated foods can be the cause of infection. Different foods, including rice, vegetables, millet gruel and various types of seafood have been implicated in outbreaks of cholera.

Hepatitis A

Although this disease is usually transmitted through other routes, it can occasionally be caught through food. It’s a contagious disease that spreads from person to person almost exclusively through fecal-oral contact, generally from person to person, or via contaminated food or water. Food contaminated with the virus is most common for transmitting hepatitis A, and outbreaks have been traced to foods contaminated by infected food workers, as well as fresh foods such as green onions and strawberries that were contaminated before entering the establishment that served them.

Viral hepatitis is the leading cause of liver cancer and the most common reason for liver transplantation.

How are foodborne illnesses prevented?

Most cases of foodborne illnesses can be prevented through proper cooking or processing of food, which kills bacteria. In addition, because bacteria multiply rapidly between 40°F and 140°F, food must be kept out of this temperature range.

Refrigerate foods promptly at 40F or lower.

Cook food to the appropriate internal temperature.

Foods are properly cooked only when they are heated long enough and at a high enough temperature to kill the harmful bacteria that cause illnesses.

Prevent cross-contamination. Bacteria can spread from one food product to another throughout the kitchen and can get onto cutting boards, knives, sponges, and countertops.

Keep raw meat, poultry, seafood, and their juices away from all ready-to-eat foods.

Handle food properly and always wash your hands before handling food and different food products.

Keep cold food cold and hot food hot.

If you are going to reheat food, make sure that it is only once and at at least 165°F.

Points to remember

Foodborne illnesses result from eating food or drinking beverages that are contaminated with bacteria, viruses, or parasites.

People at greater risk for foodborne illnesses include young children, pregnant women and their foetuses, older adults, and people with lowered immunity.

Symptoms usually resemble intestinal flu. See a doctor immediately if you have more serious problems or do not seem to be improving as expected.