Determination of Fat Content in Dairy Products

Milk and milk products are subject to strict analytical controls during processing and handling to guarantee their composition and quality. Commission Implementing Regulation (EU) 2018/150 of January 30, 2018, lays down rules for the analysis and quality evaluation of milk and milk products eligible for public intervention and private storage aid. One of the most important factors in the evaluation of milk and milk products is the fat content:

• The fat content has a direct impact on the price per liter of milk.
• Fat content is used to determine whether milk or cheese products comply with legal limits.
• Fat content is used to classify milk for the production of dairy products.

Methods to determine fat content

There are several methods for determining the fat content of milk and cheese products. The two most common methods are

The Mojonnier method

The Mojonnier method is a gravimetric method that uses organic solvents (e.g. diethyl ether) to extract the fat. The solvent is evaporated and the fat content is determined by weighing the dry fat extract.

The Gerber method

The Gerber method is a volumetric method that uses chemical reagents (e.g. sulfuric acid, detergents) to dissolve the protein encapsulating the butterfat (fat globule membranes) and separate the fat. The fat content is measured using a special glass flask called a butyrometer.