Last updated date: 09-Feb-2023

Medically Reviewed By

Medically reviewed by

Dr. Lavrinenko Oleg

Originally Written in English

Food Poisoning - Causes, Symptoms, Types, and Treatment

    Food and water can get polluted with microorganisms and poisons that cause illness, and the very young, old, and immunocompromised persons are especially vulnerable. Food hazards have become a more complicated public health concern as eating habits and lifestyles have changed, as has the availability of both local and foreign goods.

    The link between food intake and human illnesses was noticed very early, with Hippocrates (460 B.C.) reporting that there is a strong link between food consumption and human sickness. Foodborne pathogens (viruses, bacteria, and parasites, for example) are biological organisms that can cause foodborne disease. An outbreak of foodborne disease is defined as the emergence of two or more instances of identical illness caused by the consumption of a common food.


    Food poisoning 

    Food poisoning, often known as foodborne sickness, is an illness caused by consuming tainted food. The most prevalent causes of food poisoning include infectious organisms such as bacteria, viruses, and parasites, as well as their toxins.

    Foodborne disease occurs when a pathogen is swallowed with food and establishes (and generally multiplies) in the human host, or when a toxigenic pathogen establishes itself in a food product and generates a toxin, which is subsequently consumed by the human host. As a result, foodborne disease is broadly characterized as follows:


    A. Foodborne infection 

    Because an incubation period is generally involved in foodborne infections, the duration from intake to onset of symptoms is significantly longer than in foodborne intoxications.


    B. Foodborne intoxication 

    There are about 200 distinct food-borne illnesses that have been recognized. The most severe instances tend to occur in the elderly, the very young, individuals with weakened immune systems, and healthy persons exposed to a very high dosage of an organism.

    According to the Centers for Disease Control and Prevention, one in every six Americans may contract a foodborne disease each year. Infectious organisms or their toxins can contaminate food at any step in the manufacturing or processing process. Contamination can also occur at home if food is handled or prepared improperly.

    Food poisoning occurs all around the world. Many of the toxins that cause distinct food poisoning symptoms are no longer restricted to discrete geographic areas. With increased travel and the ease with which food products may be transported, it is possible that a patient will arrive at any emergency room with clinical symptoms of food poisoning.

    Recognizing unique food poisoning symptoms enables emergency health care workers to not only begin proper treatment quickly but also to alert health departments early, preventing future poisoning cases. This article examines various possible food-borne poisons and explains the mechanism of toxicity, predicted clinical presentation, and currently recognized therapy for each toxin.



    Food contamination can occur at any stage of production, including planting, harvesting, processing, storing, transporting, and preparation. The movement of dangerous organisms from one surface to another is frequently the source of cross-contamination. This is particularly problematic for fresh, ready-to-eat meals like salads and other produce. Because these foods are not cooked, dangerous organisms are not eliminated before consumption, which can result in food poisoning.

    Food poisoning is caused by a variety of bacterial, viral, and parasite agents. The table below lists some of the potential pollutants, when you could start to notice symptoms, and common methods the organism spreads.


    Risk factors

    The organism, the quantity of exposure, your age, and your health all have a role in whether you feel unwell after eating infected food. The following are high-risk groups:

    • Older adults.

    .Your immune system may not respond as fast or as effectively to pathogenic organisms as it did when you were younger

    • Pregnant women. 

    Changes in metabolism and circulation during pregnancy may increase the risk of food poisoning. During pregnancy, your response may be more severe. Your infant may also become ill on rare occasions.

    • Infants and young children. 

    Their immune systems haven't fully developed.

    • People with chronic disease.

    Having a chronic illness like diabetes, liver disease, or AIDS, as well as having chemotherapy or radiation therapy for cancer, lowers your immune response.


    Foodborne Pathogens

    Foodborne infections cause a wide range of illnesses, with serious consequences for human health and the economy. The following are the features of the most prevalent pathogenic:

    • Bacteria (Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, Clostridium perfringens, Cronobacter sakazakii, Esherichia coli, Listeria monocytogenes, Salmonella spp., Shigella spp., Staphylococccus aureus, Vibrio spp. and Yersinia enterocolitica), 
    • Viruses (Hepatitis A and Noroviruses) 
    • Parasites (Cyclospora cayetanensis, Toxoplasma gondii and Trichinella spiralis)


    Symptoms of food poisoning

    Symptoms of food poisoning

    It is more frequent than you may expect to become ill after eating food contaminated with bacteria, viruses, or parasites. Every year, an estimated 48 million Americans, or one out of every six, get food illness. Most people recover on their own, without the need for medical care.

    Abdominal cramps, nausea, vomiting, and diarrhea are the most frequent symptoms. Symptoms generally appear within hours or days of consuming contaminated food. However, symptoms may take several days or more than a week to appear. This can make determining if you have food poisoning or something else difficult. The delay also makes it difficult to link the sickness to a specific food or drink.

    The same food might have various effects on different persons. Some people may become ill after just a few nibbles. Others can consume a lot of food and have no reaction. Food poisoning is more prevalent and more dangerous among persons with compromised immune systems, babies and young children, pregnant women, and the elderly.

    Despite the wide range of types, most cases of food poisoning cause some mix of the following:

    • Diarrhea
    • Nausea
    • Vomiting

    If your symptoms are mild, you may believe you have "stomach flu" or a virus. You may be able to recover without any therapy. However, some people have such severe symptoms that they may require hospitalization.


    Specific Symptoms of Common Food Poisoning Germs

    Some bacteria can make you sick within a few hours of swallowing them. Others may make you ill after a few days. This list includes symptoms, the onset of symptoms, and frequent dietary sources for bacteria that cause food poisoning. The microorganisms are mentioned in the order in which symptoms appear.

    • Staphylococcus aureus (Staph)

    The following symptoms appear 30 minutes to 8 hours after exposure: Vomiting, nausea, and stomach cramps The majority of people also develop diarrhea. Common food sources include: Foods that have been handled but have not been cooked, such as sliced meats, puddings, pastries, and sandwiches

    • Vibrio

    Symptoms appear between 2 and 48 hours after exposure: Watery diarrhea, nausea, stomach pains, vomiting, fever, and chills are all symptoms of a bacterial infection. Common food sources include: Shellfish that is raw or undercooked, particularly oysters

    • Clostridium perfringens

    Symptoms appear 6 to 24 hours after exposure and last for 6 to 24 hours: Diarrhea and stomach cramps usually start abruptly and last less than 24 hours. Vomiting and fever are unusual. Common food sources include: Gravies; dry or precooked meals; beef or poultry, particularly big roasts

    • Salmonella

    Symptoms appear between 6 hours and 6 days following exposure: Diarrhea, fever, stomach pains, and vomiting are all symptoms of a bacterial infection. Common food sources include: Chicken, turkey, and meat that is raw or undercooked; eggs; unpasteurized (raw) milk and juice; raw fruits and vegetables

    Other sources: Many animals, including backyard poultry, reptiles and amphibians, and rodents (pocket pets)

    • Norovirus

    Symptoms appear 12 to 48 hours after exposure and include diarrhea, nausea/stomach discomfort, and vomiting. Common dietary sources include leafy greens, fresh fruits, shellfish (such as oysters), and contaminated water.

    Other sources: Infected person; touching surfaces that have the virus on them

    • Clostridium botulinum (Botulism)

    Symptoms appear between 18 and 36 hours after exposure: Double or blurred vision, drooping eyelids, and slurred speech are all symptoms of slurred speech. Difficulties swallowing and breathing, as well as a dry mouth Paralysis and muscle weakness As the disease progresses, symptoms begin in the brain and go downward. Common food sources include Foods that have been improperly canned or fermented, generally at home. Illicit alcohol produced in prison.

    • Campylobacter

    The following symptoms appear 2 to 5 days after exposure: Diarrhea (frequently bloody), stomach cramps/pain, and fever are all symptoms. Common food sources include: Uncooked or uncooked chicken, raw (unpasteurized) milk, and polluted water

    • Escherichia coli

    Severe stomach pains, diarrhea (frequently bloody), and vomiting appear 3 to 4 days after exposure. Approximately 5–10% of persons infected with E. coli develop a potentially fatal health condition. Raw or undercooked ground beef, raw (unpasteurized) milk and juice, raw vegetables (such as lettuce), raw sprouts, and contaminated water are also common food sources.


    Food poisoning symptoms

    Food poisoning symptoms can range from mild to severe. Depending on the germ you ingested, your symptoms may vary. The most common symptoms of food poisoning are:

    • Upset stomach
    • Stomach cramps
    • Nausea
    • Vomiting
    • Diarrhea
    • Fever

    It may take hours or days for symptoms to appear after consuming hazardous (infected) food or drink. If you experience food poisoning symptoms, such as diarrhea or vomiting, drink plenty of fluids to avoid dehydration (not having enough water in your body).


    Foods That Can Cause Food Poisoning

    Some foods are more commonly connected with foodborne diseases and food poisoning than others. They can carry dangerous bacteria that can make you severely sick if the food is polluted.

    • Raw foods of animal origin specifically raw or undercooked meat and poultry, raw or lightly cooked eggs, unpasteurized (raw) milk, and raw shellfish.
    • Fruits and vegetables also may get contaminated.
    • While specific foods are more likely to make you sick, any food can get contaminated in the field, during processing, or at other points in the food production chain, including cross-contamination with raw meat in kitchens.

    Meat and poultry that are raw or undercooked might make you sick. Campylobacter is present in the majority of uncooked poultry. Salmonella, Clostridium perfringens, and other bacteria may also be present. Salmonella, E. coli, Yersinia, and other bacteria can be found in raw meat.


    Food Poisoning Workup

    Gastroenteritis is typically straightforward to diagnose based on symptoms alone, with minimal requirement for medical confirmation; symptoms described by the patient are usually adequate to determine a diagnosis.

    Stool testing is required in some instances. If diarrhea is accompanied by blood or remains watery for more than a few days, physicians may request a sample to test for parasites or germs. During a rotavirus outbreak, for example, specialized testing may be needed.


    Obtain the following laboratory studies in cases of suspected food poisoning:

    • Gram staining and methylene blue staining of the stool for WBCs help to differentiate invasive from noninvasive disease.
    • Perform microscopic examination of the stool for ova and parasites.
    • Bacterial culture for enteric pathogens, such as Salmonella, Shigella, and Campylobacter organisms, if a stool sample shows positive results for WBCs or blood or if patients have fever or symptoms persisting for longer than 3-4 days.
    • blood culture if the patient is notably febrile.
    • A CBC with differential, serum electrolyte analysis, and BUN and creatinine values all aid in determining the inflammatory response and degree of dehydration.
    • In individuals on antibiotics or with a history of recent antibiotic usage, an assay for C difficile can help rule out drug-associated diarrhea.


    Food Poisoning Management

    Because the majority of instances of acute gastroenteritis are self-limiting, special treatment is not required. During the sickness, strict personal hygiene should be followed. According to certain research, only 10% of patients require antibiotic treatment.

    The most important aim is adequate fluids and electrolyte replenishment. Oral rehydration is accomplished by giving clear liquids as well as sodium- and glucose-containing solutions. Intravenous treatments are recommended for individuals who are very dehydrated or have uncontrollable vomiting.

    Absorbents (e.g., Kaopectate, aluminum hydroxide) provide patients with more control over feces timing. They do not, however, change the course of the illness or minimize fluid loss. Take note of the following:

    • An interval of at least 1-2 hours should elapse when using other medications with absorbents.
    • Antisecretory agents, such as bismuth subsalicylate , may be useful. 
    • Antiperistaltic (opiate derivatives) should not be administered in individuals who have a fever, systemic toxicity, or bloody diarrhea, or whose condition does not improve or worsen.
    • Diphenoxylate with atropine 
    • Loperamide (Imodium) is available over the counter, which increases the intestinal absorption of electrolytes and water and decreases intestinal motility and secretion. 
    • If symptoms continue for more than 3-4 days, stool cultures should be performed to establish the exact cause. If the symptoms continue and the infection is identified, a particular treatment plan should be implemented.


    In patients with suspected traveler's diarrhea, dysenteric or systemic symptoms, empiric therapy should be begun. In patients with diarrhea (>4 stools/d) for more than 3 days, as well as fever, stomach discomfort, vomiting, headache, or myalgias, treatment with an agent that covers Shigella and Campylobacter germs, is acceptable.

    The first-line treatment is a 5-day course of fluoroquinolone (e.g., ciprofloxacin, norfloxacin). TMP/SMX is an alternate treatment, however, in the tropics, resistant species are widespread. Infections caused by Vibrio cholera or Vibrio parahaemolyticus can be treated with either fluoroquinolone or doxycycline.



    Patients with severe diarrhea frequently develop an acquired disaccharidase deficit as a result of brush-border enzyme washout. As a result, it is best to avoid milk, dairy products, and other lactose-containing meals.


    When to See a Doctor?

    Doctor consultation

    See your doctor or healthcare provider if you have symptoms that are severe, including:

    • Diarrhea with blood
    • High fever (temperature in your mouth more than 102°F)
    • Frequent vomiting makes it difficult to keep drinks down (which can lead to dehydration)
    • Dehydration symptoms include little or no urine, an extremely dry mouth, and throat, and feeling dizzy upon standing up.
    • Diarrhea that lasts more than three days
    • Neurological symptoms such as blurred vision, muscular weakness, and arm tingling

    Complications of Food Poisoning

    Most people only suffer minor diseases that last a few hours to several days. Certain patients, however, require hospitalization, and some diseases result in long-term health issues or even death.

    Dehydration, a significant loss of water and vital salts and minerals, is the most common dangerous consequence of food poisoning. Dehydration should not be an issue if you are a healthy adult and consume enough fluids to replenish fluids lost through vomiting and diarrhea.

    When an infant, an elderly person, or someone with a weakened immune system or a persistent disease loses more fluids than they can restore, they can become severely dehydrated. In that scenario, kids may require hospitalization and IV hydration. Dehydration can be deadly in severe circumstances. 

    Some types of food poisoning have potentially serious complications for certain people. These include:

    • Listeria infection.

    The consequences of listeria food poisoning may be the most severe for an unborn fetus. A listeria infection might cause miscarriage early in pregnancy. Even if the mother was only moderately sick, a listeria infection later in pregnancy can result in stillbirth, preterm delivery, or a potentially deadly illness in the infant after birth. Infants who survive a listeria infection may suffer long-term brain impairment and developmental delays.

    • Escherichia coli (E. coli)

    Certain E. coli strains can induce hemolytic uremic syndrome, a severe consequence. This condition causes damage to the lining of the small blood arteries of the kidneys, which can result in renal failure. This consequence is more likely in older persons, children under the age of five, and people with weaker immune systems. If you fall into one of these risk categories, visit your doctor as soon as you see any signs of excessive or bloody diarrhea.



    To prevent food poisoning at home:

    • Hands, utensils, and food surfaces should all be washed often. Before and after handling or preparing food, thoroughly wash your hands with warm, soapy water. Wash utensils, chopping boards, and other surfaces with hot, soapy water.
    • Separate raw foods from ready-to-eat meals. Keep raw meat, poultry, fish, and shellfish apart from other foods while buying, cooking, or storing food. This helps to avoid cross-contamination.
    • Cook items until they reach a safe temperature. A food thermometer is the best way to detect if meals are cooked to a safe temperature. Cooking most meals to the proper temperature kills dangerous germs.
    • Refrigerate or freeze perishable goods as soon as possible after acquiring or preparing them. If the indoor temperature rises over 90 degrees Fahrenheit (32.2 degrees Celsius), refrigerate perishable items within one hour.
    • If you are unsure whether a food has been properly cooked, served, or kept, reject it. Food that has been kept at room temperature for an extended period of time may contain germs or poisons that cannot be eliminated by cooking. If you are dubious about a dish, do not sample it; instead, discard it. Even though food appears to be safe to eat and smells great, it may not be.



    Food poisoning may affect both a group of individuals and a single person. Food poisoning symptoms can range from minor to severe, and even lethal, such as death. Food poisoning is a risk for immunocompromised people, as well as the elderly and children. Rehydration is the most important factor in the treatment of food poisoning.

    In high-risk individuals, such as the elderly, immunocompromised, diabetics, liver cirrhosis, or those with intestinal hypomotility, empirical antibiotic treatment may be recommended. Prevention is a crucial step in the management of food poisoning because it keeps food from being contaminated, keeps it fresh, and maintains excellent hygiene.