Sampling of Milk and Milk Products

Milk is liquid product and sampling from a can or tank or a tanker may not be that difficult. This is common perception, which is wrong. Milk Fat being lighter separates out as cream layer on standing and if cream is not mixed properly the test result of such a sample will definitely be wrong. Vigorous mixing churns fat resulting in an improper sample. In Homogenized milk such problems may not occur. Milk in polypacks from different batches require batchwise sampling. If the milk is unhomogenized during filling from the storage tank variation in fat can be noticed between the initial and last filled packets. To avoid this during filling operation the speed of the agitator (to avoid churning of fat) has to be monitored and also frequent testing of milk for fat% has to be carried out. A calibrated electronic milk tester can be used for monitoring fat%.

In the case of products like milk powder, butter, ghee etc. in packs/containers where large number of units are present, it is better to use statistical methods for sampling.

Sampling can be carried out properly if one understands the product composition.In liquid milk fat being lighter tends to come to the surface on standing. To get a homogenous milk sample, proper mixing has to be done. Without a proper sample, testing is a wasteful exercise.