Buying, collection, Cooling and Transportation of Milk

1. Buying / Procurement of Milk

Key Objectives

Ensure quality raw milk

Maintain fair pricing to farmers

Prevent adulteration and spoilage

Procurement Systems

Direct procurement from farmers

Village-level collection centers

Common in cooperative models like Amul

Through middlemen/vendors

Less control over quality

Risk of adulteration

Contract farming / organized dairies

Used by companies like Nestlé

Milk Pricing Criteria

Fat % and SNF (Solids-Not-Fat)

Quality parameters (acidity, adulteration)

Seasonal variation

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Quality Testing at Purchase Point

Organoleptic test (smell, color)

Fat test (Gerber method)

Lactometer reading (SNF estimation)

Adulteration tests (urea, starch, water)

2. Collection of Milk

Village Level Collection System

Steps in Milk Collection

1. Milk pouring by farmers
2. Weighing
3. Sampling for testing
4. Quality testing (fat, SNF)
5. Recording and payment entry

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Types of Collection Systems

1. Manual collection centers
2. Automatic Milk Collection Units (AMCUs)

Digital weighing + instant fat testing

Transparent system

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Hygienic Practices

Clean utensils (preferably stainless steel)

Avoid contamination during handling

Quick transfer to cooling units

3. Cooling of Milk

Importance of Cooling

Raw milk is highly perishable

Microbial growth begins immediately after milking

Cooling preserves quality

Temperature Guidelines

Fresh milk: ~35–37°C

Must be cooled to ≤4°C within 2–3 hours

Done on the farm or at the chilling centre. Optimum temperature range for the growth of common milk microorganisms is 20 to 40⁰C.

Effect of storage tamp on bacterial growth in milk:

            Milk held for 18 hrs.                           Bacterial growth

            at tamp (⁰C)                                                    factor ( * )

                        0                                                          1.00

                        5                                                          1.05

                        10                                                        1.80   

                        15                                                        10.00 

                        20                                                        200.00

                        25                                                      1,20,000.00

Multiply initial count with this factor to get final count.

Cooling Methods

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1. Bulk Milk Coolers (BMC)

Installed at village or cluster level

Capacity: 500–5000 liters

Direct expansion cooling

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2. Chilling Centers

Large-scale cooling (below 4°C)

Milk from multiple villages aggregated

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3. Traditional Methods (less efficient)

Immersion in cold water

Ice addition (not recommended for quality milk)

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Benefits of Rapid Cooling

Slows bacterial growth

Maintains MBRT (Methylene Blue Reduction Time)

Preserves shelf life

4. Transportation of Milk

Methods of Transportation

1. Milk Cans (Traditional)

Aluminum/stainless steel cans

Used in small-scale operations

Higher contamination risk

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2. Insulated Tankers (Modern)

Stainless steel tankers

Insulated to maintain temperature

Capacity: 5,000–20,000 liters

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Cold Chain Maintenance

Milk should remain at ≤4°C

No temperature fluctuations

Avoid long transit time

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Transportation Considerations

Route planning for minimum delay

Regular cleaning (CIP – Clean-In-Place)

Avoid agitation (prevents fat separation)

Reception:

Milk Reception operations: weighing, sampling, testing, grading, unloading

Bacteriological standards of raw milk

            CFU/ ml (or gm) Grade

             < 10⁵ Very Good    

            10⁵    -   2x10⁵ Good

            5x10⁵  -  2x10⁶ Fair

             > 2x10⁶ Poor

�Pasteurized Milk  < 30,000

Milk is weighed, filtered (to remove debris), and sampled for quality at the plant.

Organoleptic check: Odor, color, consistency.

Storage: Held in insulated silos at <4°C; agitated to prevent fat separation.

5. Reception and Storage

Standardization:

Fat and SNF adjusted to meet variant specifications (e.g., 3.0% fat, 8.5% SNF for toned milk).

Cream separators (centrifuges) remove excess fat; skim milk or water added as needed.

Clarification: Centrifugal clarifiers remove fine particles (e.g., somatic cells, dirt).

Filtration: Additional filters ensure purity.

6. Pre-Processing Adjustments

7. Integrated Milk Supply Chain Flow

Farmer → Collection Center → Bulk Milk Cooler → Chilling Center → Dairy Plant → Processing

8. Critical Control Points (CCPs)

At procurement: Adulteration check

During collection: Hygiene

During cooling: Time-temperature control

During transport: Cold chain integrity

9. Common Problems & Solutions

10. Modern Innovations

• IoT-based milk quality sensors: Device → Sensor → Internet → Cloud Processing → User / Action
• GPS-enabled milk tankers
• Digital payment systems for farmers
• AI-based adulteration detection

[Farmer / Milk Producer]

↓

[Milking (Hygienic Conditions)]

↓

[Milk Collection Center (Village Level)]

↓

[Weighing & Sampling]

↓

[Quality Testing (Fat, SNF, Adulteration)]

↓

[Acceptance / Rejection]

↓

[Bulk Milk Cooler (BMC) – Rapid Cooling to ≤4°C]

↓

[Transportation (Insulated Tankers / Milk Cans)]

↓

[Chilling Center (if required)]

↓

[Dairy Processing Plant]

↓

[Processing (Pasteurization, Homogenization)]

↓

[Packaging]

↓

[Distribution to Market]

Milk Procurement to Processing Flowchart