The homogenization process emulsifies fat globules suspended in the milk so the packaged product keeps its taste, stability and texture for longer.
The more effective the homogenization process, longer the milk will remain stable and keep its commercial value.
UHT milk faces a range of limiting factors when it comes to shelf life. As a natural product, it is subject to biological processes such as sedimentation and fat separation.
Also, enzymes in the milk can cause age gelation, coagulation and – sometimes – a bitter taste.
Overcoming such obstacles is a top priority for milk producers. Aseptically packaged UHT milk has a typical shelf life of around three months, though is typically consumed well in advance of the best before date.
But quality demands differ between markets. In China, retailers are increasingly demanding imported milk with a shelf life of up to 12 months that can withstand long transport distances and temperature extremes while in transit.
This presents a business opportunity for dairy producers and highlights the importance of effective homogenization.
“We are seeing that China wants to import liquid milk from Europe – and then the question of long shelf life becomes very relevant,” explains Nicole Uvenbeck, Line Product Manager at Tetra Pak.
The longer the shelf life, the smaller the fat globules in the milk need to be. And the smaller the fat globules, the higher the required pressure and energy input from the homogenizer.
“The longer the shelf life you want, the higher the pressure you need to homogenize at,” Uvenbeck says.
“If the milk is to be shipped by container, say to China, then you really do have to consider how much it will need to be homogenized.”
Tetra Pak produces highly efficient homogenizers capable of operating at lower pressures than competitor machines.
“You can achieve the same product quality at a lower pressure with our homogenizers,” Uvenbeck says.
“So if a customer wants to extend the shelf life of their milk, for instance if seeking to export to China, I would really suggest they contact Tetra Pak!”