1.2 How Foodborne Illnesses Occur

Understanding how foodborne illness happens is the first step in preventing it. The CDC and FDA have identified specific risk factors and conditions that lead to most outbreaks.

The Big Five Risk Factors

The Big Five are the most common food handling mistakes that lead to foodborne illness outbreaks. As a manager, controlling these five factors is your top priority:

For the Exam: You must know the Big Five. Many exam questions test your ability to identify which risk factor is being violated in a scenario.

The Temperature Danger Zone

Temperature Danger Zone: 41°F to 135°F (5°C to 57°C)

This is the temperature range where bacteria multiply rapidly in TCS foods (Time/Temperature Control for Safety foods). Within this zone, certain bacteria like Salmonella, E. coli, and Clostridium perfringens can double in number every 20 minutes under the right conditions.

The rule: Keep cold food cold (41°F or below) and hot food hot (135°F or above).

Time/Temperature Control for Safety (TCS) Foods

TCS foods (formerly called "Potentially Hazardous Foods") are foods that require time and temperature control to prevent dangerous bacterial growth. The FDA Food Code adopted this term in 2005.

Complete TCS Foods List:

Animal Products:

• Meat (beef, pork, lamb)
• Poultry (chicken, turkey, duck)
• Fish and shellfish (cooked and raw)
• Eggs (except hard-boiled in shell)
• Dairy products (milk, cream, cheese, yogurt, custard, cream-based desserts)

Cooked Plant Foods:

• Cooked rice, beans, potatoes, and pasta
• Cooked vegetables
• Tofu and soy protein foods

Fresh-Cut Produce:

• Cut leafy greens (lettuce, spinach, cabbage)
• Cut melons and tomatoes
• Raw sprouts (alfalfa, bean, radish)
• Garlic-in-oil mixtures

Other TCS Foods:

• Sliced deli meats
• Gravies and sauces
• Soups and stews
• Baked potatoes
• Untreated garlic-and-oil mixtures

TCS Food Characteristics:

Foods become TCS when they have:

• pH between 4.6 and 7.5 (neutral environment for bacteria)
• Water activity above 0.85 (enough moisture for bacterial growth)
• High protein content (bacteria need protein to multiply)

Time Limits in the Danger Zone

The 4-Hour Rule: TCS foods should not remain in the danger zone for more than 4 hours cumulatively during preparation, storage, and service.

Why 4 hours? After 4 hours in the danger zone, bacteria can reach dangerous levels even if the food is later cooked or chilled.

Understanding Pathogens

Pathogen - A microorganism that causes illness. The most common foodborne pathogens are bacteria and viruses.

Biological hazards include:

• Bacteria (Salmonella, E. coli, Listeria)
• Viruses (Norovirus, Hepatitis A)
• Parasites (Cryptosporidium, Giardia)
• Fungi (molds, yeast)

Chemical hazards include:

• Cleaning chemicals
• Pesticides
• Toxic metals (lead, copper)

Physical hazards include:

• Glass fragments
• Metal shavings
• Stones or pits
• Jewelry pieces
• Bones

For the Exam: Know the difference between TCS and non-TCS foods. Expect questions asking you to identify which foods require time/temperature control.