Standardization of Milk Process

Standardization:

It is way to regulation of Fat% content in milk.

Milk Standardization 

The process of standardization can be arranged in three different ways:

Pre-standardization 
Post-standardization. 
Direct standardization.
Automatic standardization

 

The first step in all three methods is to separate whole milk into cream and skim milk. 

Pre-standardization

 The milk is standardized before being pasteurized. To adjust the fat content upward, separated cream is mixed with raw whole milk in tanks in proportions calculated to give the required fat content. To standardize to lower fat content, the raw whole milk is diluted with separated skim milk. 

After analysis and adjustment, the standardized milk is pasteurized.

Post-standardization

Pasteurized milk is mixed in tanks with either cream or skim milk, according to whether the fat content is to be adjusted upward or downward, in the same way as in the case of pre-standardization. 

However, as post-standardization involves mixing already pasteurized products, some risk of re infection is involved. Both methods, moreover, require the use of large, bulky tanks and the work of analysis and adjustment is labor-intensive.

 Direct standardization 

 The fat content is adjusted to the desired level by immediate remixing of a calculated proportion of the cream flow from the separator to the skim milk line. However, the difficulty of obtaining separated cream with a precisely controlled fat content has often made it necessary to analyze the standardized milk afterwards and perform final adjustments by mixing in tanks. At present several systems of automatic standardization are available. Their accuracy is such, that no final adjustments are necessary.

Automatic standardization 

Direct standardization begins with separation of preheated whole milk into cream and skim milk of constant fat content. A regulated amount of cream is then remixed with the skim milk in an in-line system immediately after the separator to obtain standardized milk of the required fat content.

To obtain the necessary degree of precision in the process, it is necessary to be able to control all variable parameters such as: 

1)fluctuations in the fat content of the incoming milk; 

2)fluctuations in throughput; 

3)fluctuations in preheating temperature.

Most of these variables are interdependent; any deviation in one step of the process therefore often results in deviations in all stages. 

Unless such deviations can be quickly corrected, precision of standardization will suffer and the fat content of the standardized milk will deviate from the specified value.