In our microbial world, countless bacteria coexist with us, the majority of which are benign, and some even beneficial, like Lactobacillus or LAB bacteria. However, a mere 1% of these bacterial inhabitants can wreak havoc on our health. Among this 1%, we find the notorious 7 disease-causing bacteria that have inflicted millions with food poisoning around the globe: Salmonella Spp, Escherichia coli 0157:H7, Listeria monocytogenes, Clostridium perfringens, Clostridium botulinum, Staphylococcus aureus, and Campylobacter jejuni.
These pathogens are responsible for a staggering number of foodborne illnesses annually. In the United States alone, the Centers for Disease Control and Prevention reports approximately 48 million people falling ill, 128,000 hospitalizations, and 3,000 fatalities due to foodborne diseases.
Common symptoms of food poisoning include fever, muscle pain, nausea, vomiting, and diarrhoea. While many individuals recover, the vulnerable, such as the young and elderly, face life-threatening risks. Pathogenic bacteria, alongside viruses and parasites, constitute biological hazards, one of the three recognized food safety hazards in the food industry. In any Hazard Analysis Critical Control Point (HACCP) system, a zero-tolerance approach to such hazards is imperative.
Salmonella Spp. or Salmonella:
Salmonella Spp., a gram-negative, rod-shaped facultative anaerobic bacterium, ranks as the most frequent culprit in reported outbreaks in the United States. It’s worth noting that cases of unreported infections aren’t accounted for in these figures.
Common symptoms, which can persist for up to 7 days, include nausea, chest pain, diarrhoea, and vomiting. Severe cases mainly affect young individuals, the elderly, and those with weakened immune systems.
Salmonellosis often results from consuming contaminated meat, poultry, and eggs, typically contaminated by animal faeces. Consequently, cracked eggshells should be avoided, and raw eggs should not be consumed unless pasteurized.
Escherichia coli 0157:H7:
While most strains of Escherichia coli are harmless or even beneficial to humans, Escherichia coli 0157:H7 is a gram-negative, rod-shaped bacterium responsible for numerous food poisoning cases each year. Infections often occur through the consumption of undercooked or raw meat, particularly ground meat. Kitchen utensils and surfaces used during food preparation can also harbour the bacterium.
Symptoms, including fever, abdominal pain, vomiting, and diarrhoea (often bloody), typically last up to 10 days. Unfortunately, there is no effective treatment for this type of food poisoning, as antibiotics prove ineffective.
Listeria monocytogenes:
Listeria monocytogenes, a gram-positive, rod-shaped bacterium, causes listeria, primarily affecting the nervous system. Symptoms such as fever, loss of balance, nausea, diarrhoea, vomiting, and muscle pain can last for hours or weeks.
Listeria can endure low temperatures, often infecting refrigerated food items. Reheating is crucial for ready-to-eat foods like hot dogs and deli meat to eliminate any harmful bacteria.
Clostridium perfringens:
Clostridium perfringens, a gram-positive, rod-shaped, anaerobic, and spore-forming bacterium, thrives in batch-prepared foods, often found in cafés, hotels, restaurants, buffets, and cafeterias. Food is frequently stored for extended periods before serving, making reheating essential. Refrigeration of leftover food is also crucial to slow bacterial growth.
Symptoms of C. perfringens food poisoning include vomiting, abdominal cramps, and diarrhoea, typically lasting up to 24 hours.
Clostridium botulinum:
Clostridium botulinum is a gram-positive, rod-shaped, anaerobic, spore-forming bacterium notorious for producing the deadly botulinum toxin. Unlike most bacteria, it thrives in oxygen-deprived environments, such as improperly canned goods. Botulism-contaminated home-canned items result from inadequate processing.
Botulism is a potentially fatal illness, characterized by symptoms like nausea, vomiting, weakness, dizziness, double/blurred vision, trouble breathing, and muscle coordination loss. Patients experiencing difficulty breathing may require mechanical ventilation for an extended period.
Staphylococcus aureus:
Staphylococcus aureus, a gram-positive, round-shaped bacterium, is often associated with meat, dairy, and baked goods. Contaminated foods may not exhibit spoilage signs like foul odours or discolouration. Preventing food from entering the Temperature Danger Zone (40°F to 140°F) is vital to inhibit bacterial growth.
Typical symptoms of Staphylococcal Food Poisoning include diarrhoea, vomiting, nausea, headache, and muscle, and chest pain, generally resolving within a day. Hydration is essential to combat diarrhoea, while severe cases are rare and usually self-resolving within 1 to 2 days.
Campylobacter jejuni:
Campylobacter jejuni, a gram-negative, spirally-curved bacterium, causes millions of foodborne illnesses in multiple countries. It often resides in the intestines of animals like cattle, swine, rodents, birds, and shellfish. Symptoms include nausea, diarrhoea, fever, abdominal pain, headache, and vomiting, with most people recovering without medical intervention. However, the very young and elderly may require treatment.
Most Campylobacteriosis cases result from consuming raw or undercooked meat, with transmission occurring during animal slaughter. Proper meat cooking is essential to eliminate harmful bacteria.
Preventing Disease-Causing Bacteria:
Preventing these pathogenic bacteria involves adopting routine hygiene practices:
- Maintain cleanliness: Clean cooking utensils, appliances, and food-contact surfaces regularly to prevent cross-contamination. Wash hands thoroughly with soap and water before handling food.
- Prevent cross-contamination: Separate raw and cooked foods to prevent bacterial transfer. Refrigerate cold food at 40°F (4.4°C) or below and keep hot food at 140°F (60°C) or higher to avoid the Temperature Danger Zone.
- Cook at proper temperatures: Cook food to at least 165°F (74°C) or higher, and consider investing in a food thermometer.
- Proper storage: Ensure cold foods stay cold and hot foods stay hot to inhibit bacterial growth. Avoid storing food in the Temperature Danger Zone.
