As our consumption needs have changed and with technological developments, a number of milk processing methods have appeared :

 raw milk (straight from the cow) ;
 pasteurisation ;
 sterilisation ;
 UHT ;
 and now micro-filtering.

The following explanations are offered.

Raw milk :

This is milk in its most natural state.

It is milk that has not been heated before use. It must be used within 12 hours after milking, a time period that can be extended to 24 hours if it is immediately refrigerated at 4°C. Raw milk contains natural bacteria which gives cheese its various flavours, refined aromas and sought-after textures. Most farm-produced cheeses are made from raw milk, which is also a requirement for obtaining many AOCs (Labels of Certified Origin).

Pasteurized milk :

Contrary to raw milk, pasteurization consists of heating the milk to a given temperature for a given time (around 72°C for 15 seconds) , and then quickly cooled . This process destroys almost all of the bacteria in the milk, as well as any disease agents. In this way pasteurization prolongs the shelf life of the product ; it lasts longer but loses as much of its character as its physico-chemical and intrinsic qualities.

Micro-filtered milk :

This is a new preservation technique consisting of purifying the milk. First the cream is separated from the milk, then pasteurized. For its part, the milk is filtered through extremely fine membranes separating the bacteria. The cream and milk are then re-mixed into pre-chosen proportions. This milk does not yet hold an official designation, as it is not for the time being widely available on the French market. It can be kept in cold conditions longer than pasteurized milk, and even if its taste has been partly preserved through not being heated, its physico-chemical structure has been altered.

Sterilised milk :

This milk is sold in rigid or opaque bottles or containers (often “Tetrabrick”) and does not need to be kept in cold conditions. Sterilisation consists of subjecting the milk to a temperature of 115°C for 15 to 20 minutes, or at 150°C for 2 seconds for UHT milk (Ultra High Temperature, the most consumed in France). In this way all microbial germs, including the spores are destroyed. Its preservation is considerably lengthened : 150 days ( !) and 90 days for UHT milk … In line with the logic of industrial food production, with this treatment milk can be stocked for a long time : the time to be easily transported over long distances, offered for sale without the complication of constant resupplying, and stacked in our cupboards in whole packs. “Easy” to use milk has been turned into inert matter.