ServSafe Chapter 2

Main Ideas & Lessons (Chapter 2: Understanding the Micro World)

Training Purpose / Objectives

Students will learn to:

• Identify conditions affecting the growth of foodborne bacteria (and major pathogens), including:
  • FAT TOM conditions that promote growth:
    • Food, Acidity, Temperature, Time, Oxygen, Moisture / water activity
  • Major foodborne pathogens and where they come from
  • Illnesses and symptoms caused by them
• Prevent contamination from:
  • Viruses, bacteria, parasites, fungi
  • Natural-occurring toxins (from seafood, plants, mushrooms)
  • General ways to prevent illnesses caused by these biological threats

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Biological Pathogens: What They Are

Definition

A pathogen is:

• A microorganism (seen only with a microscope)
• Harmful and can make people sick by:
  • The pathogen itself, or
  • Producing toxins that cause illness

Key Distinction

• People get sick from the toxin, not always directly from the organism.
• Toxins are described as chemical/poison-type substances.

Types of Biological Contamination

• Bacteria
• Viruses
• Parasites
• Fungi

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How Biological Contamination Happens (Common Routes)

Food handlers contaminate food when they:

• Don’t wash hands after using the restroom
• Are in contact with a sick person
• Allow someone to sneeze or vomit onto food/food-contact surfaces
• Touch dirty food-contact surfaces/equipment and then touch food

Simple mistakes that can lead to contamination include:

• Allowing ready-to-eat food to touch a surface that contacted raw meat/seafood/poultry
• Incorrect storage of food or cleaning products
• Failing to notice signs of pests

Main prevention focus (stated early):

• Practice good personal hygiene
• Avoid cross-contamination

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Common Symptoms of Foodborne Illness (Biological Pathogens)

Examples include:

• Diarrhea
• Vomiting
• Fever
• Nausea
• Abdominal cramps
• Jaundice (yellowing of skin/eyes)

Notes:

• Not every disease causes all symptoms.
• Symptoms may appear anywhere from 30 minutes to six weeks, depending on the pathogen.
• Seek medical attention, because some infections can be fatal.

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“Big Six” Pathogens (Major Highly Infectious Pathogens)

The video names six major pathogens:

• Salmonella Typhi
• Shigella species
• Non-typhoidal Salmonella
• Shiga toxin–producing E. coli (E. coli)
• Hepatitis A
• Norovirus

Additional key points:

• Often found in high numbers
• Spread to food easily
• Can cause severe illness even from small doses
• Creative project assigned: choose one “Big Six” pathogen and complete the activity via Google Classroom

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General Bacteria Concepts

Characteristics of Bacteria (General)

Bacteria are:

• Found almost everywhere
• Too small to be seen, smelled, or tasted
• Able to grow rapidly when conditions are correct
• Capable of producing toxins while growing and when dying

Main Prevention for Bacterial Illness

• The most common prevention method is:
  • Controlling time and temperature

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FAT TOM: Factors Bacteria Need to Grow (Detailed List)

Bacteria growth is described with FAT TOM:

• F — Food

  • Bacteria need nutrients
  • TCS foods support growth better than other food types

• A — Acidity

  • Best growth occurs when food has little/no acidity
  • Ideal pH range mentioned: 4.6 to 7.5
  • Examples in the range:
    • bread, raw chicken, cantaloupe, milk, cooked corn

• T — Temperature

  • “Temperature danger zone”:
    • 41°F to 135°F (about 5°C to 57°C)
  • Faster growth around:
    • 70°F to 125°F (about 21°C to 52°C)
  • Prevention guidance:
    • Keep cold foods below 41°F
    • Heat foods above 135°F

• T — Time

  • The longer TCS food stays in the danger zone, the more opportunity bacteria have to reach unsafe levels
  • Receiving cold foods: move to cold storage quickly
  • Heating: get food into the pan/oven quickly to reduce time in the danger zone

• O — Oxygen

  • Some bacteria need oxygen to grow; others grow without it

• M — Moisture (Water activity, aw)

  • Measured as water activity (aw): available moisture for growth
  • Scale: 0.0 to 1.0
  • Many bacteria grow well at aw ≥ 0.85
  • Moisture control helps limit growth (even though oxygen/moisture are harder to change, the main emphasis remains primarily on time/temperature)

Conditions the Handler Can Most Directly Control

• The factors emphasized as most controllable in practice are:
  • Time and Temperature
• Other factors are harder to control:
  • Acidity (embedded in food)
  • Oxygen (everywhere)
  • Moisture (already present in food)

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Bacterial Growth Stages (Growth Phases)

Bacteria go through stages:

• Lag phase

  • Early stage after bacteria land on food
  • They “sit there” and don’t immediately multiply

• Log phase

  • Rapid multiplication
  • Doubling speed described:
    • “Can double” within about 20 minutes
  • Illustrative progression:
    • 1 cell → 2 in 20 minutes → 4 in 40 minutes → 8 in 1 hour → 16 in ~1 hour 20 minutes → can reach billions within ~10 hours

• Stationary phase

  • Slowing of new cell production
  • Conserving resources

• Death phase

  • Cells begin dying (not instantly to zero)
  • The product is described as severely contaminated/rotting and moving into other spoilage processes

Temperature Effect on Growth (Examples)

Example scenarios given for salmonella:

• 95°F / 35°C
  • Rapid abundance within a couple of days
• 50°F / 10°C
  • “Not low enough”—could seem okay for a couple days, but becomes a problem later
• Around 44°F
  • Slower increase/plateau
  • Reduced doubling, but still risky near danger-zone-adjacent conditions

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Spores Concept

Some bacteria can form spores, described as:

• Found in dirt
• Survive cooking temperatures
• Able to later change back into a growth form

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Viruses: Key Points & Prevention

Where Viruses Come From / How They Spread

• Carried by humans and animals
• Require a living host to grow
• Do not grow in food
• Can be transferred through food and remain infectious in:
  • Food
  • Water
  • Contaminated surfaces

Common transmission path:

• Fecal-oral route
  • Restroom use → improper handwashing leaves fecal/urine traces → person touches self/food/other people

Transmission emphasized:

• Person → person
• Person → food
• Person → food-contact surfaces

Prevention Measures

• Exclude food handlers who are:
  • Vomiting
  • Have diarrhea
  • Have jaundice
• Ensure food handlers:
  • Wash hands regularly and correctly
  • Avoid bare-hand contact with ready-to-eat food
• Emphasis:
  • Normal cooking temperatures cannot destroy viruses

Viruses Highlighted

• Hepatitis A
• Norovirus (often mentioned; outbreaks such as on cruise ships)

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Parasites: Key Points & Prevention

Where Parasites Are Found

• Require a host to live and reproduce
• Most commonly found in:
  • Seafood
  • Wild game
  • Food processed with contaminated water (e.g., produce)

Prevention Measures

• Purchase from approved, reputable suppliers
• Cook to minimum internal temperatures (most parasites are killed with proper cooking)
• For fish served raw/undercooked:
  • Freeze correctly by the manufacturer (freezing requirements before consumption)

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Fungi (Mold / Yeast): Key Points & Prevention

Fungi Examples and Effects

• Mold

  • Spoils food and sometimes causes illness
  • Can produce toxins
  • Can grow in almost any condition, especially:
    • Acidic food
    • Low water activity
  • Cooler/freezer temperatures slow growth but do not reliably destroy it

• Yeast

  • Spoils food quickly
  • May produce a smell/taste of alcohol
  • May show white/pink discoloration or slime
  • May bubble

Prevention Measures

• Mold/food contamination:
  • “Throw out” moldy food unless mold is naturally part of the food
  • If unsure how to identify mold, consult a culinary instructor
• Yeast:
  • Throw away food containing yeast (not all yeast is “bad,” but “bad yeast” is the concern; instructor guidance suggested)
• Note on “good” molds:
  • Naturally occurring molds may exist in some foods (example: blue cheese)

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Biological Toxins: Sources and Prevention

Seafood Toxins

• Cannot be smelled or tasted
• Cannot be destroyed by freezing or cooking
• Sources described:
  • Fish that have eaten smaller fish containing toxins
  • Shellfish that have eaten toxic algae
• Mercury mentioned:
  • Absorbed into fish from the water ecosystem
  • Toxin type depends on what the fish/shellfish eats

Mushroom Toxins

• Illness linked to eating toxic wild mushrooms
• Caused by toxic mushrooms mistaken for edible ones
• Prevention:
  • Purchase from approved, reputable suppliers
  • Avoid harvesting wild mushrooms yourself
  • Use trained professionals for wild mushroom use

Plant Toxins / Plant-Related Food Illnesses

• Can occur when plants come from unapproved suppliers
• Can occur when certain plants aren’t cooked correctly
  • Example: uncooked kidney beans
• Prevention:
  • Purchase from approved, reputable suppliers

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Program Wrap-Up / Assigned Work

• The instructor concludes Chapter 2.
• Students are instructed to:
  • Rewind/pause/review slides for bacteria/viruses/toxins not covered verbally
  • Use the video as a resource while completing the Google Form for Chapter 2
  • Also watch the Chapter 2 and 3 contamination video from the National Restaurant Association

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Speakers / Sources Featured

• Mr. Dan Delcher — Certified ServSafe instructor (Essex County Schools of Technology)
• National Restaurant Association — referenced for an additional contamination video (Chapter 2 & 3)
• Google Classroom / Google Form — platform used for assigned chapter projects/activities