HOMOGENIZING OF CHEESE MILK:   Homogenizing of cheese milk is used for the following types of cheese:  Blue Cheese, Feta, Romi, Dimiyati, Akawi, Nabulsi, Baladi and similar cheese.    By means of homogenization, fat globules are broken down into smaller sized globules.  The total surface area increase and the creation of new fat globule membranes become necessary. The main purpose of homogenization is to prevent creaming (large globules rising to the top), but several other properties of milk are changed too.    The fat globule must now also surround itself with some of the milk casein and this causes more moisture to be bound up.  In other words:  if too large a division of fat globules takes place, increasing homogenizing will cause the moisture content to increase.  No over homogenizing should occur. If that happens, a crushing of fat globules by which larger or smaller number of fat globules flows together, you then obtain the opposite of the desired effect.   

The normal procedure today is to have the whole milk preheated in the regen section to approximately 50 C., after which it is separated so we get cream at approximately 20% fat.  This cream then goes to the homogenizer and is treated at a pressure of 170 - 200 atm. (2500 - 3000 psi), after which it is mixed again with skim milk and the mixture is pasteurized at the desired temperature, depending on the type of cheese. 

 It is important that the cream does not contain air at homogenization.  It can be expedient to have a balance tank for cream before homogenization, so the cream under storing can expel air. 

 As a normal rule a strong homogenization gives a large water binding effect and thereby larger moisture content in the finished cheese.  This means that a higher homogenization pressure will give higher moisture content.  By increasing the homogenization temperature the cream viscosity will be less and cream will with the same opening in the homogenizer be treated at a lower pressure, which means the effect will be less.  If the opening is made smaller, so that the homogenization pressure is kept constant, a higher temperature gives a larger homogenization effect and the water percentage increases. 

It is also valid, that the lower the cream fat percentage is, the higher the water binding will be in the cheese. 

 Water binding ability in cheese has a great influence on cheese quality.  It is not only a question about moisture bound loose or tightly, it is also a question of if the protein matter are swelling right, to give cheese of good quality.  Therefore, homogenization of cheese milk plays a decisive role on quality of the cheese, where homogenized milk is used. 

 If the cheese mass has not reached the right degree of swelling, there will not exist the right relation between lactic acid bacteria.  They will not develop right and propionic acid bacteria will take over.  This is because the swelling of the protein matter is of important for the salt penetration into the cheese.  (Salt inhibits propionic acid bacteria.)  If we do not have the right swelling, the result will be that the middle part of the cheese will be soft, brown and with a too high pH, as the propionic bacteria use lactic acid.

If the salt distribution does not happen properly, a salt sample will always show that salt content in the soft area of the cheese is considerably lower than in the area where the cheese is normal. 

 The conclusion is not, if the cheese has a high or low salt percentage, but if salt penetration has gone too slow.