Explain with the help of flow diagrams, the manufacture of sterilized, homogenized and flavoured milk.

Sterilization (Pasteurization and Ultra-High Temperature Processing - UHT)

Sterilization primarily involves eliminating harmful microorganisms. Two main methods are employed: pasteurization and Ultra-High Temperature (UHT) processing. Pasteurization extends shelf life while maintaining a more natural flavor. UHT processing provides a much longer shelf life at ambient temperatures.

Flow Diagram – Pasteurization

(Note: Image is for illustrative purposes only. A real exam would require a hand-drawn or digitally created diagram.)

1. Raw Milk Reception & Clarification: Milk is received, tested for quality (antibiotics, somatic cell count), and clarified to remove gross impurities.
2. Preheating: Milk is preheated to around 40-60°C.
3. Pasteurization: Milk is heated to 72°C for 15 seconds (HTST – High-Temperature Short-Time) or 63°C for 30 minutes (LTLT – Low-Temperature Long-Time).
4. Cooling: Rapidly cooled to 4°C.
5. Packaging: Packaged in sterile containers.

Flow Diagram – UHT Processing

(Note: Image is for illustrative purposes only. A real exam would require a hand-drawn or digitally created diagram.)

1. Raw Milk Reception & Clarification: Same as Pasteurization.
2. Preheating: Milk is preheated to around 90-95°C.
3. UHT Treatment: Milk is rapidly heated to 135-150°C for 2-5 seconds.
4. Homogenization (Often done after UHT): See next section.
5. Aseptic Cooling: Quickly cooled under sterile conditions.
6. Aseptic Packaging: Packaged in sterile, multi-layered containers.

Homogenization

Homogenization reduces the size of fat globules in milk, preventing creaming and improving texture. It's typically done after sterilization, although it can sometimes precede UHT treatment.

Flow Diagram – Homogenization

(Note: Image is for illustrative purposes only. A real exam would require a hand-drawn or digitally created diagram.)

1. Milk Intake: Heated milk from sterilization passes into the homogenizer.
2. High-Pressure Passage: Milk is forced through a small gap at high pressure (typically 2000-3000 psi).
3. Fat Globule Reduction: The pressure causes fat globules to break down into smaller, more uniform sizes.
4. Outlet: Homogenized milk exits the machine.

Flavoring

Flavoring involves adding ingredients like chocolate, vanilla, or fruit extracts to the milk. This is done aseptically to maintain sterility.

Flow Diagram – Flavoring

(Note: Image is for illustrative purposes only. A real exam would require a hand-drawn or digitally created diagram.)

1. Sterilized & Homogenized Milk Intake: Milk flows into the flavoring tank.
2. Flavor Addition: Concentrated flavorings (e.g., chocolate powder, vanilla extract) are added in precise proportions.
3. Mixing: Gentle mixing ensures uniform distribution of the flavoring.
4. Quality Check: Sensory evaluation (taste, color, aroma) and microbiological testing.
5. Aseptic Packaging: Packaged in sterile containers.

Quality Control: Throughout the entire process, rigorous quality control measures are implemented, including regular testing for bacterial contamination, somatic cell counts, fat content, and flavor consistency. Adherence to FSSAI standards is critical.

Process	Objective	Temperature (°C)	Duration
Pasteurization (HTST)	Microbial inactivation, extended shelf life	72	15 seconds
UHT Processing	Sterilization, long shelf life at ambient temperature	135-150	2-5 seconds
Homogenization	Reduce fat globule size, prevent creaming	~90 (milk temperature)	Instantaneous

The manufacture of sterilized, homogenized, and flavored milk is a complex process involving precise control of temperature, pressure, and aseptic conditions. Each stage – sterilization, homogenization, and flavoring – contributes to the final product's safety, stability, and consumer appeal. The increasing demand for convenient and shelf-stable dairy products necessitates continuous innovation in processing technologies, with a focus on energy efficiency and minimizing environmental impact. Future trends may include the adoption of more sustainable packaging materials and the exploration of novel flavor combinations.