How to make Disinfectant Dettol Basic 6 Home Economics Lesson Note

Learning Objectives

By the end of the lesson, pupils should be able to:

• Explain the meaning of disinfectant
• Discuss uses of disinfectant
• Identify different types of disinfectants
• List the ingredients used in making disinfectant
• Identify infections that can be prevented by using disinfectants
• Prepare Dettol-type disinfectant

Lesson Content

What is a Disinfectant?

Definition

A disinfectant is a chemical substance that destroys or prevents the growth of harmful microorganisms such as bacteria, viruses, fungi, and other pathogens on surfaces, objects, and in some cases, on living tissue.

Key Characteristics of Disinfectants

• Antimicrobial action: Kills or inhibits microorganisms
• Chemical composition: Contains active ingredients that target pathogens
• Concentration-dependent: Effectiveness depends on proper dilution
• Time-dependent: Requires contact time to work effectively
• Surface application: Primarily used on non-living surfaces

Difference Between Disinfectants and Related Products

Uses of Disinfectants

1. HOUSEHOLD USES

Surface Cleaning:

• Kitchen countertops and cutting boards
• Bathroom fixtures (toilets, sinks, bathtubs)
• Door handles and light switches
• Floor cleaning and mopping
• Garbage cans and waste areas

Laundry Applications:

• Adding to wash water for heavily soiled items
• Disinfecting baby clothes and diapers
• Cleaning cloth diapers
• Sanitizing towels and bed linens

Water Treatment:

• Purifying drinking water in emergencies
• Cleaning water storage containers
• Pool and spa maintenance
• Well water treatment

2. HEALTH AND HYGIENE USES

Personal Hygiene:

• Hand washing (when soap unavailable)
• Foot soaks for fungal infections
• Mouth rinse (properly diluted)
• Bath water additive for skin conditions

Medical Applications:

• Wound cleaning (when properly diluted)
• Equipment sterilization
• Surface preparation before medical procedures
• Hospital and clinic cleaning

3. COMMERCIAL AND INSTITUTIONAL USES

Food Service:

• Restaurant surface cleaning
• Food preparation area sanitization
• Equipment cleaning
• Dining area maintenance

Educational Institutions:

• Classroom cleaning
• Playground equipment sanitization
• Cafeteria maintenance
• Restroom cleaning

Types of Disinfectants

1. ALCOHOL-BASED DISINFECTANTS

Active Ingredients:

• Isopropyl alcohol (70-99%)
• Ethyl alcohol (ethanol)

Characteristics:

• Fast-acting
• Evaporates quickly
• Effective against many pathogens
• Flammable

Uses:

• Hand sanitizers
• Surface cleaning
• Medical equipment
• Electronics cleaning

2. CHLORINE-BASED DISINFECTANTS

Active Ingredients:

• Sodium hypochlorite (bleach)
• Calcium hypochlorite
• Chlorine dioxide

Characteristics:

• Very effective against bacteria and viruses
• Strong odor
• Can be corrosive
• Inexpensive

Uses:

• Water treatment
• Surface disinfection
• Laundry bleaching
• Pool sanitization

3. PHENOLIC DISINFECTANTS

Active Ingredients:

• Phenol and phenol derivatives
• Cresols
• Pine oil

Characteristics:

• Effective against bacteria
• Persistent antimicrobial action
• Strong distinctive odor
• Can be toxic in high concentrations

Uses:

• Household cleaners (like Dettol)
• Floor cleaners
• Veterinary applications
• Industrial cleaning

4. QUATERNARY AMMONIUM COMPOUNDS (QUATS)

Active Ingredients:

• Benzalkonium chloride
• Cetylpyridinium chloride

Characteristics:

• Low toxicity
• No strong odor
• Effective against bacteria
• Less effective against viruses

Uses:

• Fabric softeners
• Hand sanitizers
• Surface cleaners
• Food service sanitizers

Infections Prevented by Disinfectants

1. BACTERIAL INFECTIONS

Common Household Bacteria:

• E. coli: Causes food poisoning, diarrhea
• Salmonella: Food poisoning, gastroenteritis
• Staphylococcus: Skin infections, food poisoning
• Streptococcus: Throat infections, skin infections

Prevention Methods:

• Regular surface disinfection
• Kitchen hygiene maintenance
• Bathroom cleaning
• Hand hygiene promotion

2. VIRAL INFECTIONS

Common Household Viruses:

• Influenza: Flu symptoms, respiratory illness
• Norovirus: Stomach flu, vomiting, diarrhea
• Rhinovirus: Common cold
• Coronavirus: Respiratory illness

Prevention Methods:

• Surface disinfection in common areas
• Doorknob and handle cleaning
• Shared equipment sanitization
• Proper hand hygiene

3. FUNGAL INFECTIONS

Common Household Fungi:

• Athlete’s foot: Foot fungal infection
• Ringworm: Skin fungal infection
• Candida: Yeast infections
• Mold: Respiratory problems, allergies

Prevention Methods:

• Bathroom moisture control
• Foot hygiene maintenance
• Proper ventilation
• Regular cleaning of damp areas

4. PARASITIC INFECTIONS

Common Parasites:

• Giardia: Intestinal parasites
• Cryptosporidium: Water-borne parasites
• Pinworms: Intestinal worms

Prevention Methods:

• Water treatment and purification
• Surface cleaning in affected areas
• Proper hygiene education
• Contaminated area disinfection

Ingredients for Making Dettol-Type Disinfectant

PRIMARY INGREDIENTS

1. PINE OIL

Function: Main active antimicrobial ingredient Properties:

• Derived from pine trees
• Natural antiseptic properties
• Pleasant pine scent
• Effective against bacteria and fungi

Amount: 200ml per liter of final product

2. ISOPROPYL ALCOHOL

Function: Additional antimicrobial agent and solvent Properties:

• 70% concentration preferred
• Fast-acting disinfectant
• Helps dissolve other ingredients
• Evaporates quickly

Amount: 150ml per liter of final product

3. CASTOR OIL

Function: Emulsifier and skin conditioning agent Properties:

• Helps mix oil and water components
• Reduces skin irritation
• Adds viscosity to mixture
• Natural moisturizing properties

Amount: 50ml per liter of final product

SECONDARY INGREDIENTS

4. CAUSTIC SODA (SODIUM HYDROXIDE)

Function: pH adjuster and saponification agent Properties:

• Strong alkaline compound
• Helps create stable emulsion
• Converts oils to soap-like substances
• Must be handled carefully

Amount: 10-15 grams per liter Safety: Always add to water, never water to caustic soda

5. DISTILLED WATER

Function: Main solvent and diluting agent Properties:

• Pure water without minerals
• Prevents contamination
• Allows proper mixing
• Creates final volume

Amount: 400ml per liter of final product

6. FOOD COLORING (OPTIONAL)

Function: Aesthetic appearance Properties:

• Makes product visually appealing
• Helps with brand recognition
• Traditional Dettol color is brown/amber
• Safe, non-toxic colorants

Amount: Few drops as needed

7. FRAGRANCE (OPTIONAL)

Function: Pleasant scent Properties:

• Masks chemical odors
• Adds consumer appeal
• Should be antimicrobial-safe
• Use sparingly

Amount: 2-3ml per liter

Step-by-Step Preparation of Dettol-Type Disinfectant

EQUIPMENT NEEDED

Mixing Equipment:

• Large mixing bowl (stainless steel or glass)
• Wooden or plastic stirring spoon
• Measuring cups and spoons
• Funnel for bottling
• Clean storage bottles

Safety Equipment:

• Rubber gloves
• Safety goggles
• Apron or old clothes
• Well-ventilated area
• First aid supplies nearby

PREPARATION PROCESS

STEP 1: SAFETY PREPARATION (5 minutes)

1. Set up workspace: 
   1. Choose well-ventilated area
   2. Cover work surface with newspaper
   3. Ensure good lighting
   4. Have water source nearby
2. Put on safety equipment: 
   1. Wear rubber gloves
   2. Put on safety goggles
   3. Wear protective clothing
   4. Tie back long hair
3. Prepare equipment: 
   1. Clean all mixing equipment
   2. Measure all ingredients
   3. Have storage containers ready
   4. Check that caustic soda is fresh

STEP 2: MIXING THE OIL PHASE (10 minutes)

1. Combine oils: 
   1. Pour pine oil into mixing bowl
   2. Add castor oil slowly
   3. Stir gently to combine
   4. Mix until uniform consistency
2. Add alcohol: 
   1. Slowly add isopropyl alcohol
   2. Stir continuously while adding
   3. Mix until well combined
   4. Set aside temporarily

STEP 3: PREPARING CAUSTIC SOLUTION (15 minutes)

1. Prepare water: 
   1. Measure distilled water
   2. Use cool, not hot water
   3. Pour into separate container
   4. Never use metal containers for caustic soda
2. Add caustic soda: 
   1. SAFETY CRITICAL: Always add caustic soda to water, NEVER water to caustic soda
   2. Add small amounts at a time
   3. Stir constantly while adding
   4. Allow to cool if mixture heats up
   5. Stir until completely dissolved
3. Cool the solution: 
   1. Allow solution to reach room temperature
   2. This may take 10-15 minutes
   3. Do not proceed until cool
   4. Check temperature carefully

STEP 4: COMBINING PHASES (10 minutes)

1. Slow addition: 
   1. Very slowly add oil mixture to caustic solution
   2. Add drop by drop initially
   3. Stir constantly during addition
   4. Watch for emulsification to begin
2. Continuous mixing: 
   1. Stir vigorously but carefully
   2. Continue for 5-10 minutes
   3. Mixture should become creamy
   4. Color should become uniform
3. Check consistency: 
   1. Should be smooth and creamy
   2. No oil separation visible
   3. Uniform color throughout
   4. Pleasant pine scent evident

STEP 5: FINAL ADJUSTMENTS (5 minutes)

1. Add coloring: 
   1. Add food coloring drop by drop
   2. Stir well between additions
   3. Achieve desired amber/brown color
   4. Stop when satisfied with color
2. Add fragrance: 
   1. Add fragrance if desired
   2. Use very small amounts
   3. Stir well to distribute
   4. Test scent strength
3. Final mixing: 
   1. Stir mixture thoroughly
   2. Ensure complete integration
   3. Check for any separation
   4. Allow to rest for 5 minutes

STEP 6: QUALITY TESTING (10 minutes)

1. Visual inspection: 
   1. Check for uniform color
   2. Look for oil separation
   3. Ensure smooth consistency
   4. Verify pleasant appearance
2. pH testing: 
   1. Use pH strips if available
   2. Should be slightly alkaline (pH 8-9)
   3. Adjust if necessary
   4. Record pH value
3. Dilution test: 
   1. Mix small amount with water
   2. Should form milky white solution
   3. No oil floating on top
   4. Good mixing characteristics

STEP 7: BOTTLING AND STORAGE (10 minutes)

1. Prepare bottles: 
   • Clean bottles thoroughly
   • Rinse with distilled water
   • Allow to air dry completely
   • Use funnel for filling
2. Fill bottles: 
   • Pour carefully to avoid spills
   • Leave small air space at top
   • Wipe bottle exteriors clean
   • Secure caps tightly
3. Labeling: 
   • Label with contents
   • Include preparation date
   • Add dilution instructions
   • Include safety warnings

SAFETY PRECAUTIONS

During Preparation

• Always work in ventilated area
• Wear protective equipment at all times
• Add caustic soda to water, never reverse
• Keep ingredients away from children
• Have water available for emergencies
• Work slowly and carefully

Storage Safety

• Store in cool, dry place
• Keep away from heat sources
• Label clearly with contents
• Store away from children and pets
• Check containers regularly for leaks

Usage Safety

• Always dilute before use (1:10 ratio with water)
• Test on small area first
• Avoid contact with eyes
• Do not mix with other chemicals
• Use gloves when handling concentrate

Proper Dilution and Usage

DILUTION RATIOS

General Surface Cleaning:

• 1 part disinfectant : 10 parts water
• Mix 100ml disinfectant with 1 liter water
• Suitable for floors, counters, bathrooms

Heavy-Duty Disinfection:

• 1 part disinfectant : 5 parts water
• Mix 200ml disinfectant with 1 liter water
• For heavily contaminated areas

Light Cleaning:

• 1 part disinfectant : 20 parts water
• Mix 50ml disinfectant with 1 liter water
• For routine maintenance cleaning

APPLICATION METHODS

Surface Cleaning:

1. Prepare dilution in spray bottle or bucket
2. Apply to surface and allow contact time
3. Wipe with clean cloth after 5-10 minutes
4. Rinse with clean water if necessary

Floor Mopping:

1. Add diluted solution to mop bucket
2. Mop floors as usual
3. Allow to air dry
4. No rinsing required for most floors

Quality Control and Shelf Life

QUALITY INDICATORS

• Appearance: Uniform amber/brown color
• Consistency: Smooth, no separation
• Dilution: Forms milky solution in water
• Scent: Pleasant pine fragrance
• Effectiveness: Kills germs as intended

SHELF LIFE

• Homemade disinfectant: 6-12 months
• Store in cool, dry place
• Check regularly for separation
• Discard if color changes significantly
• Replace if strange odor develops

Multiple Choice Exercise – Week 2

1. What is the main active ingredient in Dettol-type disinfectants? a) Alcohol b) Pine oil c) Caustic soda d) Water 
2. Which safety rule is most important when making disinfectant? a) Wear gloves only b) Work quickly c) Add caustic soda to water, never reverse d) Use hot water 
3. What ratio should be used for general surface cleaning? a) 1:5 (disinfectant:water) b) 1:10 (disinfectant:water) c) 1:20 (disinfectant:water) d) 1:1 (disinfectant:water) 
4. Which infection is commonly prevented by using disinfectants? a) Malaria b) E. coli c) Diabetes d) Asthma 
5. How long is the shelf life of homemade disinfectant? a) 1-2 months b) 3-4 months c) 6-12 months d) 2-3 years 

Answers: 1-b, 2-c, 3-b, 4-b, 5-c

Homework – Week 2

1. Define disinfectant and explain its importance in the home.
2. List 5 types of infections that can be prevented by using disinfectants.
3. Write the complete ingredients list for making Dettol-type disinfectant.
4. Explain 3 important safety precautions when making disinfectants.
5. Describe how to properly dilute disinfectant for general cleaning.