All of them have been milked from the cows in the Farm of Saint Isidro which has been run by the Monks of “La Trapa of Saint Isidro of Dueñas” for more than fifty years now.
Once it has been pasteurized and cooled down (so it does not need to be boiled), it has been packaged inside a closed circuit process in order to get a product with a maximum guarantee of quality.
Every production and dispensing process is subject to the most demanding control measures.
What is the pasteurized milk?
It is the milk that has been treated with a temperature lower than the boiling point, between 70-75º C (158 – 167ºF) for 15 seconds. It destroys pathogens and most of the bacteria without affecting the milk qualities. The vitamin losses are kept at minimum, being preserved in a cool environment between 0-4º C (32 – 39.2ºF) from the moment of production thereof.
Flash pasteurization process
It is also known as –continuous pasteurization- or HTST (High Temperature Short Time), this treatment involves applying a temperature between 72-73ºC (161.6 – 163.4ºF) to the milk for 15 to 20 seconds.
This pasteurization is made in plate heat exchangers and the route which the milk does inside is as follows:
The milk gets to the exchanger system at approximately 4ºC (39.2ºF) coming from a regulator tank. In the first section, it is heated by regeneration.
In this regeneration or preheating section, raw milk is heated up to approximately 58ºC (136ºF) thanks to the milk already pasteurized whose temperature is utilized at this regeneration area.
When coming out of the regeneration section, milk goes through the filter which eliminates the contaminants that may have, then milk goes to the heat exchangers of the section or heating area where it is heated up to the pasteurization temperature, this is between 72-73ºC (161.6 – 163.4ºF) by means of hot water.
Once the core temperature has been reached, it goes to the section of temperature retention. This section can be formed from an external pipe or a retardant included inside the exchanger. The most common one is the retention pipe in which the time that milk is retained takes around 15 to 20 seconds.
When leaving this retention area, milk goes towards a bypass valve. This valve, if the milk has not reached the temperature between 72-73ºC (161.6-163.4ºF), makes it automatically return to the regulator or the supply tank so that it is processed later on but if the milk reaches the temperature between 72-73ºC (161.6 – 163.4ºF), then it goes to the regeneration or preheating section where it is cooled down by means of the raw milk up to 18ºC (64.4ºF).
From this point, the milk goes to the cooling section where two zones can be distinguished: one of them is through where cold water is circulated and the other one is through where ice water is circulated being this way how the milk route comes to an end, usually coming out of the exchanger at a temperature of 4ºC (39.2ºF)
From here, it goes to the packaging machine and it is stored in a refrigerating chamber at 4ºC (39.2ºF) until being delivered to the shops.