It is common for those who open a yogurt, seeing that there is a thin film of cloudy liquid on the surface, a sort of serum, empty it into the sink before drinking it.
However, what we are seeing is nothing different from the composition of the yogurt itself .
How to squeeze a sponge
This cloudy liquid that looks like whey is, in effect, whey made up primarily of water, protein, and lactose, plus other nutrients like calcium. That is, it has nothing bad for health: we can ingest it without problems .
In fact, it is only part of the yogurt, as if it were a sponge formed by a protein network in which that serum is retained, as Miguel Ángel Lurueña explains in his book They don’t bundle you with food :
If the manufacturing and handling processes are not adequate, that structure may be affected and syneresis phenomena may occur, that is, the release of that serum. It’s like we’re squeezing that sponge. This can happen, for example, if the processing temperature is too high or if there are sudden movements during transport. If the phenomenon is very pronounced, it is considered a defect, but it does not necessarily mean that the yogurt is unfit for consumption.