Скачать или смотреть What is Chilling Center in a Dairy Plant

#food_processing #esculentascience #dairy
Milk chilling is a crucial step in the dairy processing chain. The primary purpose of chilling raw milk immediately after milking is to inhibit microbial growth, which can affect the quality, safety, and shelf life of the milk.

Here's a breakdown of why and how milk is chilled:

1. **Importance of Chilling Milk**:

**Microbial Growth**: Milk is a nutritious medium, making it susceptible to rapid bacterial growth. Many bacteria multiply faster at warmer temperatures. Chilling the milk slows down this microbial activity.
**Enzymatic Activity**: Raw milk contains enzymes that can degrade its quality over time. Chilling helps to slow down these enzymatic reactions.
**Freshness and Flavor**: Keeping milk chilled helps in retaining its freshness and natural flavor.
**Shelf Life**: Rapid chilling and maintaining a cold chain throughout the distribution process extends the milk's shelf life.

2. **Chilling Process**:

**On-Farm Chilling**: On larger dairy farms, milk is often chilled immediately after milking using bulk milk coolers (BMC). The milk is directly transferred from the milking system to these coolers, where it's rapidly cooled to 4°C (39.2°F) or even lower.
**Chilling Centers**: In areas with smaller farms, farmers might transport the milk to a nearby chilling center. These centers have large chilling units, and the milk from several farms is pooled and chilled before it's sent to a processing plant.
**Direct Expansion (DX) Bulk Coolers**: These are the most common type of bulk coolers, where the milk is cooled by direct contact with evaporator coils filled with refrigerant.
**Ice Bank Coolers**: Here, the milk doesn't come in direct contact with the evaporator coils. Instead, an ice bank is built up during non-milking periods, and this ice cools the milk during milking times.
**Instant Cooling Systems**: Some advanced systems use instant cooling techniques, where milk is chilled very rapidly using plate heat exchangers.

3. **Transportation**: Once chilled, it's essential to maintain the cold chain during transportation. Milk tankers that transport the milk to processing plants are insulated and equipped with cooling systems to keep the milk at the desired temperature.

4. **Challenges**:

**Electricity**: In many regions, especially rural areas in developing countries, a consistent power supply can be a challenge. Some farms or chilling centers use diesel generators as backup.
**Small Scale Production**: For small-scale farmers, investing in chilling equipment might not be economical. Community-based chilling centers or shared resources can be a solution in such cases.

5. **Alternative Methods**: For areas where chilling infrastructure is lacking, other preservation methods like lactoperoxidase (LP) systems or bactofugation can be used to extend the milk's shelf life temporarily. However, chilling remains the preferred method due to its efficiency and efficacy.

In summary, chilling is one of the most vital steps in ensuring the quality and safety of milk. It helps in extending the milk's shelf life and ensures that the milk reaches the consumer in the best possible condition.