Milk chiller
The function of a milk chiller is to rapidly and efficiently cool raw milk immediately after milking and maintain a low temperature, typically around 4°C (39°F), until it can be transported for processing. This process is critical for preventing bacterial growth, preserving the milk's quality, and extending its shelf life.
Key functions of a milk chiller :
Inhibits bacterial growth : Freshly drawn milk is warm (around 35–37°C), which is an ideal temperature for bacteria to multiply. Rapidly chilling the milk to 4°C significantly slows down this microbial growth, which is essential for ensuring the milk is safe for consumption.
Preserves milk quality and nutrients : By controlling the temperature, a milk chiller helps maintain the milk's original taste, texture, aroma, and nutritional content. This prevents spoilage and undesirable changes caused by bacterial or enzymatic activity.
Extends shelf life : Properly chilled milk can be stored for 24 to 48 hours without compromising its quality. This provides greater flexibility for dairy farmers and collection centers to manage milk pickup and delivery schedules.
Ensures hygiene and safety : The use of stainless steel and built-in automatic cleaning systems (known as clean-in-place or CIP systems) in modern chillers minimizes the risk of contamination and ensures strict hygiene standards are met.
Enables bulk storage and transportation : The chiller and its insulated storage tank allow large volumes of milk from multiple milking sessions or farms to be collected and held securely before being transported to a dairy processing plant.
Enables bulk storage and transportation : The chiller and its insulated storage tank allow large volumes of milk from multiple milking sessions or farms to be collected and held securely before being transported to a dairy processing plant.
Milk chillers operate on refrigeration principles, but can differ in their specific cooling methods.
Direct expansion (DX) cooling : The tank's walls or jacket contain a refrigerant that directly cools the milk. An internal agitator ensures that the milk is cooled uniformly to the target temperature.
Ice bank (IBT) cooling : This system stores cooling energy by building ice around a refrigerant coil in a tank of water. When milk needs to be chilled, the cold water from the melted ice is circulated to cool the milk, making it energy-efficient for locations with unreliable power.
Plate heat exchanger (PHE) cooling : In this method, milk flows through a series of plates while a cooling medium, such as chilled water, flows on the other side, providing extremely fast and instant cooling
