Agromisa 
Interdev Agroalimentaire  

Systems for cooling milk

	Type de fiche	Techniques/Technologies
	Date(s) de l’expérience	1995
	Mise en œuvre	Agromisa(Pays Bas)
	
	Zone géographique	; 
	Mots clés	LAIT; REFRIGERATION

Contexte
The three techniques described here are based on the assumption that quantities of  up to 30 litres of milk are handled in a collection-can.
Problématique / Objectifs
Pasteurized milk can be kept for about one week at 4-10 o C, unprocessed milk (raw  milk) has to be consumed within one day if not cooled. If cooled, it can be pasteurised after 1 or 2 days. So cooling is essential both before processing milk in any other products and after pasteurisation of fresh milk before consumption.In the tropics, the required temperature cannot be achieved without refrigeration or the use of ice.
Description/Mise en oeuvre
1. Ice-cones: A metal cone filled with ice is inserted in the collection can. The cone fits sufficiently tight in the can to prevent milk splashing out during transport and handling. This system is feasible for long distance transport from the farms to a collection or processing point, if cooling prior to transport is impossible. The cones and the ice can be taken to the farms by the milk collecting truck. The ice should be transported in an insulated box. The cones must be properly cleaned and sanitized after use. With this system, the milk can be cooled to 5-10 o C during transport. 

2. Ice-water tanks: The collecting cans can be inserted to their necks in a tank filled with water and ice, or in a tank where very cold water is circulated. The lids of the collection cans must be loosened, to allow for aeration of the milk during cooling. The whole tank with ice-water can be closed with a a lid to protect the milk from flies and dust. For best results, the tank should be insulated. If water is circulated through the tank, the milk cools down faster.

3. Cooling rings: A perforated tubular ring can be put around the neck of the collecting can with warm milk. This ring can be connected to a source of ice-water, in order to spray water on the outer surface of the can. The water can be collected at the bottom and recirculated into the refrigeration equipment or ice-water reservoir. Source:Berg, J.C.T. van den (1988) Dairy Technology in the Tropics and Subtropics. Pudoc, Wageningen. p.53-59
Enseignements
Key Factors
- Availability of ice or facilities for cooling water. 
- Means for circulating the ice-water. 
- Good collecting cans for milk. 
- Welding skills to adapt ideas to the local needs

Auteur : Rob Witte
Saisie le : 26/11/2001 

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