Common Foodborne Diseases and Their Prevention

Every year, millions of people around the world fall sick after consuming contaminated food. According to the World Health Organization (WHO), an estimated 600 million people – nearly 1 in 10 globally – suffer from foodborne illnesses annually, leading to approximately 420,000 deaths. These diseases are caused by harmful bacteria, viruses, parasites, or toxins that enter the body through contaminated food or water. Understanding the types, causes, and prevention of foodborne diseases is essential for anyone involved in food production, handling, or simply cooking meals at home.

What are foodborne diseases? 🔗

Foodborne diseases, often called food poisoning, occur when a person consumes food or drink contaminated with pathogenic microorganisms or their toxins. As the U.S. Food and Drug Administration (FDA) explains, these illnesses can be caused by bacteria, viruses, parasites, chemicals, or toxins. Symptoms typically include diarrhea, vomiting, abdominal cramps, nausea, and fever. In most healthy individuals, these symptoms resolve within a few days, but in vulnerable populations – such as young children, elderly adults, pregnant women, and immunocompromised individuals – the consequences can be severe or even fatal.

Foodborne diseases are broadly classified into two categories: foodborne infections and foodborne intoxications. An infection occurs when a person ingests food containing live pathogens that then multiply inside the body and cause illness. An intoxication, on the other hand, occurs when a person consumes food containing toxins that have already been produced by microorganisms – the pathogen itself may or may not be present at the time of consumption.

Common bacterial foodborne diseases 🔗

Bacteria are the most frequent cause of foodborne diseases and are responsible for the majority of hospitalizations and deaths linked to contaminated food. Here are some of the most significant bacterial foodborne illnesses.

Salmonellosis 🔗

Salmonellosis is one of the most widely reported foodborne infections worldwide. It is caused by the bacterium Salmonella, a Gram-negative, rod-shaped organism with over 2,500 recognized serotypes. According to a peer-reviewed study published in PMC, salmonellosis is primarily a gastrointestinal infection with high incidence rates across both developed and developing countries.

Common sources of Salmonella include raw or undercooked poultry, eggs, unpasteurized milk, and fresh produce. Symptoms such as diarrhea, fever, and abdominal cramps typically appear 12-72 hours after ingesting the contaminated food and usually resolve within four to seven days without treatment. However, severe cases – especially in young children and elderly people – may require hospitalization.

Botulism 🔗

Botulism is a rare but extremely serious foodborne intoxication caused by the neurotoxin produced by Clostridium botulinum, an anaerobic, spore-forming bacterium. The USDA’s Food Safety and Inspection Service (FSIS) notes that symptoms of botulism usually appear within 12 to 36 hours after consumption and include nausea, vomiting, blurred vision, difficulty speaking and swallowing, muscle weakness, and in severe cases, respiratory failure.

Improperly home-canned or preserved low-acid foods – such as green beans, corn, asparagus, and meats – are the most common sources of foodborne botulism. The bacterium thrives in low-oxygen, low-acid environments (pH above 4.6), making improperly processed canned goods a high-risk food category. According to the University of Florida IFAS Extension, while botulism has a relatively low incidence rate, its mortality rate is significantly high if left untreated – approximately 17.3% compared to 0.5% for Salmonella.

Staphylococcal food poisoning 🔗

Staphylococcus aureus produces heat-stable toxins in food, making it a classic example of foodborne intoxication. This bacterium is commonly found on human skin, in the nose, and in throats. When food handlers with poor hygiene contaminate cooked, protein-rich foods – such as ham, salads, cream-filled pastries, and dairy products – and these foods are left at room temperature, S. aureus can multiply rapidly and produce enterotoxins.

Symptoms appear quickly, often within 1 to 6 hours of eating contaminated food, and include severe nausea, vomiting, and abdominal cramps. The illness is usually self-limiting and resolves within 24-48 hours. Because the toxin is heat-stable, reheating food does not eliminate the risk once the toxin has been produced.

Clostridium perfringens 🔗

Clostridium perfringens is another bacterium commonly linked to foodborne illness. It is found on raw meat, poultry, and in the intestines of humans and animals. Illness caused by this bacterium is sometimes referred to as the “buffet germ” because outbreaks often occur when large batches of food – especially meat and poultry dishes – are prepared in advance and kept warm for extended periods. According to CDC estimates published in the Emerging Infectious Diseases journal, C. perfringens causes approximately 1 million episodes of foodborne illness annually in the United States alone.

Listeriosis 🔗

Listeriosis is caused by Listeria monocytogenes, a bacterium that can grow even at refrigerator temperatures. It primarily affects pregnant women (potentially causing miscarriage or stillbirth), newborns, older adults, and those with weakened immune systems. Common food sources include unpasteurized dairy products, ready-to-eat deli meats, smoked seafood, and soft cheeses. Though less common than Salmonella or Campylobacter infections, listeriosis has a high fatality rate and is responsible for a significant proportion of foodborne disease-related deaths.

Viral foodborne diseases 🔗

Viruses account for a large share of foodborne illnesses, particularly in developed countries. Unlike bacteria, viruses cannot multiply in food – they use food merely as a vehicle to enter the human body, where they then replicate.

Norovirus 🔗

Norovirus is the single most common cause of foodborne illness. CDC data indicates that norovirus accounts for roughly 58% of all foodborne illnesses in the United States. It spreads easily through contaminated food, water, surfaces, and direct contact with infected individuals. Symptoms include explosive vomiting, watery diarrhea, nausea, and abdominal pain. The illness is usually short-lived (1-3 days) but is highly contagious, making it a frequent cause of outbreaks in settings such as restaurants, cruise ships, and institutions.

Hepatitis A 🔗

The WHO notes that Hepatitis A virus can be transmitted through food – particularly raw or undercooked seafood and contaminated fresh produce – and can lead to prolonged liver disease. Unlike most other foodborne viral infections that resolve in a few days, Hepatitis A has a long incubation period of 2-6 weeks and may cause jaundice. Vaccination is the most effective prevention strategy for Hepatitis A.

Parasitic foodborne diseases 🔗

Parasites are less common than bacteria or viruses as causes of foodborne illness, but they can lead to serious and chronic health problems.

Toxoplasmosis 🔗

Toxoplasma gondii is a parasite found in the environment, particularly in cat feces and contaminated soil. Humans can become infected by consuming raw or undercooked meat (especially pork, lamb, or venison), unwashed produce, or contaminated water. For most healthy individuals, the infection is mild or asymptomatic. However, it can be extremely dangerous for pregnant women (risking harm to the unborn child) and immunocompromised individuals. In fact, T. gondii is one of the leading causes of foodborne disease-related deaths.

Trichinellosis 🔗

Trichinella spiralis is a parasitic roundworm that causes trichinellosis. Infection typically results from eating undercooked or raw pork or wild game meat containing Trichinella larvae. Symptoms include nausea, diarrhea, muscle pain, and fever. Proper cooking of meat to safe internal temperatures effectively kills the parasite.

Other parasites 🔗

Other parasites associated with food include Giardia, Cryptosporidium, Cyclospora cayetanensis, and tapeworms such as Taenia species. These organisms typically enter the food chain through contaminated water or soil and are especially prevalent in regions with poor sanitation.

How food becomes contaminated 🔗

Food can become contaminated at any stage of the food chain – from farm to fork. During production, crops may be exposed to contaminated irrigation water or animal manure. During processing, improper handling or equipment sanitation can introduce pathogens. During storage, inadequate temperature control allows bacteria to multiply. And during preparation, cross-contamination from raw to cooked foods or poor hygiene by food handlers can transfer harmful organisms.

Some of the most common causes of contamination include inadequate cooking temperatures, improper food storage (leaving perishable foods at room temperature for too long), poor personal hygiene of food handlers, and cross-contamination between raw and ready-to-eat foods.

Prevention of foodborne diseases 🔗

The good news is that most foodborne illnesses are preventable. The U.S. Centers for Disease Control and Prevention (CDC) recommends a simple, effective framework built around four core steps: Clean, Separate, Cook, and Chill.

Clean: wash hands and surfaces often 🔗

Handwashing is the first line of defense. Hands should be washed with soap and water for at least 20 seconds before, during, and after food preparation, and especially after handling raw meat, poultry, seafood, eggs, or flour. All cutting boards, utensils, and countertops should be washed with hot, soapy water after preparing each food item. Fresh fruits and vegetables should be rinsed under clean, running water before consumption.

Separate: prevent cross-contamination 🔗

Raw meat, poultry, seafood, and eggs should be kept separate from other foods at every stage – while shopping, storing, and preparing food. The FoodSafety.gov guidelines recommend using separate cutting boards and utensils for raw animal products and ready-to-eat foods. Raw meats should be stored in sealed containers at the bottom of the refrigerator to prevent juices from dripping onto other items.

Cook: reach safe internal temperatures 🔗

Cooking food to the correct internal temperature is the most reliable way to kill harmful pathogens. A food thermometer is essential – visual checks like colour or texture are not dependable indicators of food safety. Key temperatures to remember include 74°C (165°F) for all poultry and reheated leftovers, 71°C (160°F) for ground meats, and 63°C (145°F) for whole cuts of beef, pork, lamb, and fish.

Chill: refrigerate promptly 🔗

Bacteria multiply most rapidly in the “Danger Zone” – temperatures between 4°C (40°F) and 60°C (140°F). Perishable foods should never be left at room temperature for more than two hours (or one hour if the ambient temperature exceeds 32°C/90°F). Refrigerators should be maintained at 4°C (40°F) or below, and freezers at -18°C (0°F) or below. Leftovers should be divided into shallow containers for faster cooling.

Special precautions for high-risk foods 🔗

Certain foods carry higher contamination risks and need extra care. These include raw or undercooked poultry and eggs, unpasteurized milk and juice, raw sprouts, unwashed fruits and vegetables, raw shellfish, and raw dough or batter. For home canning, it is critical to use pressure canners for low-acid foods and follow established guidelines from authorities like the USDA to prevent botulism. The FSIS also advises discarding any canned goods that appear swollen, gassy, or damaged.

The global burden of foodborne diseases 🔗

Foodborne diseases are not just a health issue – they carry enormous economic consequences. The WHO estimates that unsafe food costs low- and middle-income countries around US$ 110 billion annually in lost productivity and medical expenses. Children under five bear a disproportionate burden, accounting for 40% of all foodborne disease cases and an estimated 125,000 deaths each year. Strengthening food safety systems, improving surveillance, educating food handlers, and empowering consumers with knowledge are all crucial steps toward reducing this burden.

What do you think? How confident are you in the food safety practices followed in your own kitchen or your local food supply chain? Could better awareness of the “Clean, Separate, Cook, Chill” framework make a meaningful difference in reducing foodborne illnesses in your community?

References

1. https://www.who.int/news-room/fact-sheets/detail/food-safety
2. https://www.fda.gov/food/outbreaks-foodborne-illness/foodborne-pathogens
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC8143179/
4. https://www.fsis.usda.gov/food-safety/foodborne-illness-and-disease/illnesses-and-pathogens/botulism
5. https://ask.ifas.ufl.edu/publication/FS104
6. https://pmc.ncbi.nlm.nih.gov/articles/PMC3375761/
7. https://www.cdc.gov/food-safety/prevention/index.html
8. https://www.foodsafety.gov/keep-food-safe/4-steps-to-food-safety