Food safety encompasses the handling, preparation, and storage of food to prevent foodborne illness. Foodborne diseases affect an estimated 600 million people annually worldwide, causing 420,000 deaths. Most foodborne illnesses are preventable through proper food handling practices.
Foodborne Pathogens
Bacteria
Salmonella. The most common cause of bacterial foodborne illness in the United States. Associated with poultry, eggs, unpasteurized milk, fresh produce, and contaminated water. Symptoms: diarrhea, fever, abdominal cramps 6–72 hours after exposure, lasting 4–7 days. Most cases resolve without treatment; antibiotics are reserved for severe cases or immunocompromised patients.
Campylobacter jejuni. The most common cause of diarrheal illness in the US. Associated with undercooked poultry, unpasteurized milk, and contaminated water. Can trigger Guillain-Barré syndrome (peripheral neuropathy) in rare cases.
Escherichia coli O157:H7. A Shiga toxin-producing strain associated with undercooked ground beef, raw produce (especially leafy greens and sprouts), and unpasteurized milk and juice. Causes severe bloody diarrhea and hemolytic uremic syndrome (HUS) — acute kidney failure in children. Proper cooking of ground beef to 160°F (71°C) kills E. coli.
Listeria monocytogenes. A psychrotrophic bacterium that grows at refrigeration temperatures. Associated with ready-to-eat foods (deli meats, hot dogs, soft cheeses, smoked fish, and unpasteurized dairy). Particularly dangerous for pregnant women (causes miscarriage, stillbirth, neonatal infection), older adults, and immunocompromised individuals.
Clostridium botulinum. Produces botulinum toxin, a potent neurotoxin that causes botulism (descending flaccid paralysis). Associated with improperly home-canned, low-acid foods (canned vegetables, meats, fish). Infant botulism is associated with honey. Treatment includes antitoxin and supportive care.
Clostridium perfringens. Associated with improperly stored meat and poultry (cafeteria and buffet settings). Causes acute diarrhea and abdominal cramps 8–12 hours after ingestion. Often called the cafeteria germ.
Viruses
Norovirus. The leading cause of foodborne illness in the US. Highly contagious (10–100 virus particles can cause infection). Associated with contaminated food (salads, sandwiches, raw produce, shellfish) and person-to-person spread. Causes acute gastroenteritis (vomiting, diarrhea, nausea, abdominal cramps) for 1–3 days. No specific treatment; supportive care with rehydration.
Hepatitis A. A vaccine-preventable virus transmitted through contaminated food (frozen berries, green onions, shellfish) and water. Causes acute hepatitis (jaundice, fatigue, nausea, abdominal pain). Vaccination is recommended for all children, travelers to endemic areas, and high-risk groups.
Hepatitis E. Transmitted through undercooked pork, wild boar meat, and contaminated water. Particularly dangerous in pregnant women (20% mortality in third trimester).
Parasites
Toxoplasma gondii. Associated with undercooked meat (especially pork, lamb, game), contaminated produce, and cat feces. Toxoplasmosis is a major concern in pregnancy (congenital toxoplasmosis) and immunocompromised individuals.
Trichinella spiralis. Found in undercooked pork and game meat (bear, wild boar). Causes trichinellosis (myalgia, periorbital edema, fever). Rare in modern pork production but still a concern from wild game.
Cryptosporidium parvum. A protozoan parasite found in contaminated water and produce. Causes watery diarrhea that can be prolonged (1–2 weeks). Resistant to chlorine — outbreaks have occurred in swimming pools and recreational water.
The Four Core Food Safety Practices
Clean. Wash hands with soap and water for at least 20 seconds before handling food, after using the bathroom, after handling raw meat/poultry/seafood, and after touching pets. Wash cutting boards, utensils, counters, and produce thoroughly. Rinse fresh fruits and vegetables under running water (do not wash meat, poultry, or eggs — this spreads bacteria).
Separate. Use separate cutting boards for raw meat, poultry, seafood, and produce. Keep raw meat juices away from ready-to-eat foods in shopping carts, grocery bags, and the refrigerator. Never place cooked food on a plate that held raw meat.
Cook. Use a food thermometer to ensure internal temperatures reach safe levels. Minimum safe temperatures: poultry (165°F/74°C), ground meats (160°F/71°C), steak/roasts/fish (145°F/63°C with 3-minute rest), pork (145°F/63°C), eggs (cook until yolk and white are firm), and leftovers (165°F/74°C). Microwave cooking requires stirring, rotating, and standing time for even heating.
Chill. Refrigerate perishable foods within 2 hours (1 hour if the temperature is above 90°F). Keep the refrigerator at or below 40°F (4°C). Keep the freezer at or below 0°F (−18°C). Thaw food in the refrigerator, cold water (change water every 30 minutes), or the microwave — never on the counter. Marinate foods in the refrigerator.
Food Preservation
Refrigeration and freezing. Slow microbial growth and enzymatic reactions. Freezing at 0°F (−18°C) stops microbial growth but does not kill microorganisms.
Canning. Seals food in airtight containers and heats to destroy pathogens and spoilage organisms. Low-acid foods require pressure canning to reach 240–250°F (116–121°C) to kill C. botulinum spores.
Pasteurization. Heat treatment of milk, juice, and other liquids to destroy pathogenic bacteria without significantly altering taste or nutritional value. High-temperature short-time (HTST) pasteurization at 161°F (72°C) for 15 seconds is standard for milk.
Fermentation. Uses beneficial microorganisms (lactobacillus, yeast) to preserve food and create characteristic flavors. Examples: yogurt, cheese, sauerkraut, kimchi, pickles, sourdough bread.
Drying, curing, and pickling. Remove water (reducing water activity for microbial growth), add salt, sugar, or acid to inhibit spoilage organisms.
Food Safety Regulations
In the United States, food safety is regulated by the FDA (Food and Drug Administration — most foods except meat, poultry, and processed eggs) and the USDA Food Safety and Inspection Service (meat, poultry, and processed eggs). The Food Safety Modernization Act (FSMA), signed in 2011, shifted the focus from responding to contamination to preventing it. The Hazard Analysis Critical Control Points (HACCP) system identifies and controls hazards throughout the food production process.
Global Food Safety Challenges
Foodborne illness is a greater burden in low- and middle-income countries due to inadequate food safety infrastructure, contaminated water, and limited access to refrigeration. Globalization of the food supply means that contaminated food in one country can cause outbreaks worldwide. Antimicrobial resistance, food fraud (economically motivated adulteration), and climate change impacts (increased pathogen growth in warmer temperatures) are emerging concerns.
Summary
Food safety is essential for preventing foodborne illness. The four core practices — clean, separate, cook, chill — prevent most foodborne diseases. Bacteria (Salmonella, Campylobacter, E. coli, Listeria), viruses (norovirus, hepatitis A), and parasites (Toxoplasma, Cryptosporidium) are the primary culprits. Proper cooking temperatures and timely refrigeration are critical. Food allergies require vigilance in label reading and communication. Food safety regulations have shifted toward prevention. Global food safety improvements are needed to address the disproportionate burden in low-resource settings.