Food poisoning

The symptoms of food poisoning range from mild to severe. They can start appearing from a few hours to several weeks after consuming contaminated food. In most cases, symptoms resolve on their own or with appropriate home care within a few days of contracting the infection.

Early Signs

These symptoms are the first to appear and are common to most types of food poisoning. These include:

• Nausea
• Vomiting
• Diarrhea
• Dull stomach ache, cramps, or sharp pain

Dealing with constant stomach aches? Here are some of the causes of stomach ache along with information about when to consult a doctor.

Other Symptoms

The other symptoms might include:

• Headache
• Dizziness
• Intense thirst
• Diarrhea which may contain blood or mucus
• Dehydration
• Decreased urination
• Cold and clammy skin
• Slow pulse
• Fever
• Chills
• Muscle ache
• Lack of energy
• Loss of appetite

Long-term Severe Symptoms

Individuals can also experience several long-term severe symptoms in some cases, which include:

• Reactive arthritis (sometimes known as Reiter's Syndrome)
• Severe vomiting
• Profuse watery diarrhea
• Severe dehydration
• Confusion
• Seizures
• Muscle weakness
• Double vision
• Slurred speech

Did You Know?

Stomach flu/viral gastroenteritis and food poisoning often share similar symptoms. The difference lies in the transmission. Stomach flu is mostly caused by viruses and is transmitted from person to person, while food poisoning is caused by the ingestion of contaminated food and water.

Food poisoning is caused by the contamination of food by either microbes or other toxins.

A. Microbial contamination

1. Bacteria: It is the most common cause of food poisoning. The symptoms and severity of the infection depend on the type of bacteria that has contaminated the food. Some of the bacteria that cause food poisoning are:
   • Campylobacter: These bacteria usually contaminate raw or undercooked meat, raw milk, and contaminated water. The incubation period (time between exposure to the bacteria and the onset of symptoms) is 2-5 days. The symptoms generally last for a week.
   • Salmonella: Contaminated raw or undercooked meat, raw eggs, milk, and other dairy products are the main sources of these bacteria. Symptoms typically appear between 12 to 72 hours.
   • Listeria: These bacteria are found in “ready-to-eat” foods such as pre-packed sandwiches, hot dogs, cooked sliced meats, and soft cheeses. Symptoms can appear from a few days to several days. Food poisoning usually resolves within 3 days.
     Note of caution: Pregnant women are 10 times more likely than others to get Listeria infection, which can cause complications such as miscarriage, stillbirth, or premature birth.
   • Escherichia coli (E. coli): These bacteria normally inhabit the intestines of several animals and humans. Most types are harmless, but some can cause food poisoning. They contaminate food such as undercooked beef and unpasteurized milk. Symptoms usually start appearing within 1 to 8 days of contracting the bacteria and last for a few days.
   • Shigella: Any food such as fruits and vegetables washed in contaminated water can be exposed to Shigella. Symptoms typically develop within seven days of eating contaminated food and last for up to a week.
   • Bacillus cereus: This microorganism mainly develops in improperly stored food. Infection is characterized by diarrhea and vomiting.
   • Staphylococcus: It is most commonly found in undercooked meats, eggs, and dairy products.
   • Vibrio: This type of bacteria is commonly found in coastal water and can contaminate oysters, fish, and shellfish. Symptoms can start appearing 1 day after infection and usually resolve in 3 days.
   • Clostridium: This bacteria contaminates food that is cooked in large batches. Common food items that may contain this bacteria include poultry and meat.
2. Other less common microbes
   1. Parasites: Parasites are organisms that derive their nutritional requirements from other living organisms. Symptoms of food poisoning caused by parasites develop within 10 days of exposure. Common examples include:
      • Giardia intestinalis
      • Cryptosporidium
      • Entamoeba histolytica
   2. Viruses: Viruses that can cause food poisoning spread through contaminated water and can also spread via an infected person while preparing or handling food. Common viruses include:
      • Rotavirus
      • Adenovirus
      • Parvovirus
   3. Fungi: Several fungi may cause food poisoning by producing harmful chemicals that contaminate foods. Common examples include:
      • Alternaria
      • Aspergillus
      • Candida
      • Fusarium

B. Non-microbial

In some cases, harmful chemicals are already present in food, which can cause food poisoning. Fish and shellfish may contain toxins produced by algae or bacteria present in water. Unwashed produce may also cause food poisoning due to the presence of pesticides used during crop production. The contaminants can be of:

• Vegetable origin (Mushrooms)
• Animal origin (Shellfish)
• Chemicals (Flavouring agents, coloring agents, and preservatives)

How does food get contaminated?

Food is not only contaminated in the kitchen. It can be exposed to contamination during its production, harvesting, processing, storing, shipping, and preparation. Microbes can cause food poisoning if they are not washed off or killed before consumption. The following factors can keep the microbes alive to cause food poisoning:

• Consuming partially cooked food
• Keeping cooked food unrefrigerated for a long period
• Storing packaged food at the wrong temperature
• Promptly refrigerating hot food
• Keeping raw foods such as beef, poultry, and eggs together with ready-to-eat foods

The microbes of food poisoning can also spread through an infected person via:

• Eating food touched by the infected person
• Cross-contamination (where harmful bacteria are spread between food, surfaces, and equipment)
• Consuming ready-made contaminated food
• Touching contaminated surfaces and objects such as handrails, elevator buttons, utensils, and doors while eating or handling food
• Sharing food and beverages with an infected person

Any individual can suffer from food poisoning, but certain groups of people are more prone to it. These groups include:

1. Children younger than 5 years of age
   Children have an underdeveloped immune system, increasing their chances of infection. Food poisoning can lead to severe diarrhea and dehydration in children. They are also three times more likely to be hospitalized if they contract a Salmonella infection.
2. Pregnant women
   Pregnant women are at a higher risk for food poisoning. Studies suggest that they are ten times more likely to contract a Listeria infection.
3. Older people above 65 years of age
   The immune system of older adults is often compromised, making them more susceptible to infections.
4. People with weakened immune systems
   Some individuals have weakened immune systems, which can lead to recurrent food poisoning. Conditions contributing to a weakened immune system include:
   • Diabetes
   • Liver disease
   • Kidney disease
   • Cancer
   • HIV infection
5. Consuming certain foods
   Some food items are more prone to microbial contamination and, thus, food poisoning. These include:
   • Raw meat
   • Unpasteurized milk
   • Fish
   • Shellfish
   • Eggs
   • Poultry
   • Cheese
   • Raw fruits and vegetables
   • Nuts
   • Spices
   • Beef
   • Salad
   • Seafood
   • Sprouts
   • Raw flour
   The frequent consumption of these foods increases the risk of food poisoning.
6. Other factors
   Several other factors can contribute to food poisoning, including:
   • Purchasing food from unauthorized sources
   • Cooking food at incorrect temperatures
   • Storing food without refrigeration
   • Practicing poor personal hygiene, such as not washing hands before eating or serving food
   • Using contaminated food and utensils

There are no specific tests to diagnose food poisoning. In most cases, symptoms are mild and last for a few hours. In the event of severe poisoning, the following steps can help your doctor determine the cause of your food poisoning:

1. History Taking
   It is the first step in establishing food poisoning. Your doctor will ask a series of questions to identify the agent of food poisoning. The questions may include:
   • Recent meals you have consumed
   • Recent places of travel, if any
   • Other individuals you know who are experiencing similar symptoms
   • Medicines you are currently taking
   Your doctor will also inquire about the symptoms you are experiencing. This information aids in establishing the cause and type of food poisoning.
2. Physical Examination
   This examination is conducted to observe changes in the body based on the symptoms experienced. During a physical exam, your doctor may:
   • Examine blood pressure to check for signs of dehydration
   • Check temperature to confirm fever
   • Assess the abdomen using a stethoscope
   • Inspect for tenderness or pain in the abdomen through tapping
3. Laboratory Tests
   The type of contaminant is diagnosed through several tests. The microbial contaminant is assessed using samples of blood, urine, vomit, or stool. These tests also reveal the severity of poisoning and usually include:
   • Stool Tests: The stool is examined for the presence of bacteria, parasites, or blood.
   • Blood Tests: Blood tests are performed to check for any signs of complications such as dehydration and kidney abnormalities. This includes assessing the levels of electrolytes and other markers of kidney function.
   • Urine Tests: This test is also conducted to check for bacterial infections.
4. Imaging Tests
   
   • Abdominal Ultrasound: This imaging test examines organs in the abdomen, including the intestine, liver, gallbladder, spleen, pancreas, and kidneys. It is a highly useful imaging modality for evaluating patients with acute abdominal symptoms.
   • Abdominal X-ray: In some cases of poisoning, an abdominal X-ray may be used to check the presence and location of ingested substances. Toxins that may be visible on X-rays include iron, lead, arsenic, and other metals.

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Food poisoning can be prevented by practicing hygiene while storing, handling, or preparing food. The following measures can reduce the chances of food poisoning:

A. Follow Safe Practices

1. While Buying Food Items

• Buy foods such as meat and seafood from hygienic outlets.
• Do not buy food items whose expiry has elapsed.
• Do not purchase undercooked or raw meats.
• Buy only pasteurized milk and cheese.
• Do not buy cracked or leaked eggs.
• Choose fresh fruits and vegetables.
• Check for any damage, rust, or dents on cans while buying beverages.
• Take frozen and refrigerated items from an authentic grocery store.

2. While Storing Food

• Keep raw meat, poultry, and seafood in separate bags during refrigeration to avoid cross-contamination.
• Keep the temperature of the main section below 4°C.
• Store food as per the instructions on the label.
• Keep cooked leftovers quickly in the refrigerator.
• Keep raw cereals and dough away from the reach of children.

3. While Cooking and Handling Food

• Do not leave cut vegetables and fruits uncovered.
• Cook food thoroughly.
• Cook eggs until both the yolk and white are firm.
• Discard food that appears suspicious in look or smell.
• Ensure that food is steaming all the way through while reheating.
• Avoid reheating food more than once.

4. While Traveling

• Drink only boiled or bottled water.
• Avoid eating raw vegetables and salads.
• Avoid buying food from unhygienic vendors.

5. While Dining Out

• Avoid dishes that contain undercooked eggs, sprouts, meat, poultry, or seafood.

B. Maintain Proper Hygiene

• Wash your hands, counters, and cutting surfaces between the preparation of different foods.
• Use glass or plastic cutting boards for chopping vegetables or meat instead of wooden boards for ease of cleaning.
• Wash fresh fruits and vegetables under running water.
• Avoid contact with sick persons while handling or preparing food.
• Ensure sanitation of the kitchen floors, utensils, and other articles.

The first step in maintaining hygiene is having clean hands. Hand washing can prevent about 30% of diarrhea-related illnesses. Learn the right way to wash your hands!

C. Clean the Refrigerator Frequently

The refrigerator should be cleaned thoroughly along with removable parts. The following measures should be taken while cleaning the refrigerator:

• Dispose of contaminated food in a garbage bag.
• Wash the container in which contaminated food was stored with soap and water.
• Avoid leaving food out of the refrigerator for more than 2 hours.

The treatment of food poisoning is based upon the cause and symptoms. The most important goal of the therapy is to maintain hydration and electrolyte balance.

Fluid Therapy

• Most cases of mild dehydration can easily be managed at home through fluid therapy.
• It is advised to drink plenty of fluids like water and coconut water to compensate for water loss and prevent dehydration.
• Oral rehydration solutions (ORS) are preferred over other clear fluids for managing diarrhea.
• Patients with severe dehydration and persistent vomiting may require hospital admission for continuous monitoring of electrolyte levels.
• Enteral (oral or nasogastric) and intravenous fluids (saline solution and lactate Ringer’s solutions) are given to patients facing difficulty in taking fluids due to nausea and vomiting, and to correct electrolyte levels.

Medications

Antibiotics

Antibiotics are mostly used to treat food poisoning caused by bacteria. Some commonly used antibiotics include:

• Metronidazole
• Ceftriaxone
• Azithromycin

Antiemetics

Antiemetic medications are used to control nausea and vomiting. Commonly used antiemetic medications include:

• Ondansetron
• Metoclopramide

Antidiarrheal Medications

These medications relieve symptoms of diarrhea and are used only in patients who are unable to maintain a well-hydrated status. Medications include:

• Diphenoxylate
• Loperamide

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1. Keep a watch on fluid intake
   It is advised to have plenty of fluids like fresh fruit juices, coconut water, and clear soups. In case of severe vomiting, take small sips of fluids at regular intervals. Mothers of infected infants should ensure that their babies are getting enough breast milk.
2. Have ice chips
   If you have difficulty digesting fluids, try sucking on ice chips, which also helps with rehydration. Ice chips should not be given to small children.
3. Consume BRAT diet
   B.R.A.T stands for bananas, rice, applesauce, and toast. These foods should be included in the diet as they help smooth the stool and compensate for nutrient loss from vomiting and diarrhea. It is also advised to consume smaller, easy-to-digest meals at regular intervals.
4. Try herbal remedies
   In most cases, food poisoning can be managed by simple home remedies like:
   • Ginger (Adrak): Possesses anti-inflammatory, anti-viral, and anti-bacterial properties. It eases nausea and can be taken raw or boiled in water or tea.
   • Apple cider vinegar (ACV): Soothes an irritated stomach, reducing nausea, vomiting, and abdominal cramps. Add 1 teaspoon of ACV to a glass of warm water and drink 30 minutes before meals.
   • Yogurt (Dahi): Contains beneficial bacteria that help maintain gut health and reduce watery diarrhea. It should be included in every meal for those suffering from food poisoning.
   • Cinnamon (Dalchini): Has antibacterial and antiviral properties that combat food poisoning, reducing stomach pain and bloating.
   • Turmeric (Haldi): Contains curcumin, which has anti-inflammatory properties. It can be consumed by adding to warm water or milk.
   • Basil (Tulsi): Possesses antispasmodic properties, reducing spasms and providing gastroprotective benefits.
   • Peppermint (Pudina): Soothes the stomach and helps treat bloating and gas, most effectively consumed as tea.
   • Triphala: Known to improve digestive health and aid in nutrient absorption.
   • Coriander (Dhania): Has healing properties that alleviate symptoms of upset stomach and diarrhea.
   • Asafoetida (Hing): Strengthens the digestive system and has antiviral and antibacterial properties. It can be added to meals or consumed with lukewarm water.
   • Licorice (Mulethi): Promotes healing of an inflamed stomach and treats indigestion.
   • Rice water: Used, especially in infants, to reduce diarrhea.
   • Chamomile tea: Acts as a digestive relaxant, helping treat gastrointestinal disturbances like diarrhea and vomiting.
5. Avoid certain foods
   Certain food items should be avoided as they can upset the stomach and cause indigestion, aggravating diarrhea and vomiting. These include:
   • Milk
   • Greasy and spicy foods containing chili, black pepper, and garlic
   • Drinks with caffeine, such as coffee, tea, and soft drinks
   • Fatty junk foods such as fried foods, pizza, and fast foods
   • Foods and drinks with high amounts of simple sugars, such as sweetened beverages and packaged fruit juices
6. Take proper rest
   Proper rest should be taken even after therapy completion to ensure complete recovery and healing of the digestive system.
7. Try heating pad
   Patients suffering from severe abdominal pain can use a heating pad to relieve cramps.
8. Say no to alcohol
   Alcohol can cause stomach inflammation and increase gastric acid secretion, thus increasing feelings of nausea and vomiting.

Untreated food poisoning can lead to the following complications:

• Chronic diarrhea
• Inflammatory bowel disease (a condition characterized by inflammation of the small and large intestine)
• Irritable bowel syndrome (a condition marked by abdominal pain)
• Arthritis
• Hemolytic uremic syndrome (a kidney condition resulting from the destruction of red blood cells, which can impair kidney function)
• Guillain-Barre syndrome (a neurological disorder where the immune system attacks the nervous system)
• Nervous system infections, such as meningitis