https://phys.org/news/2018-07-technology-shelf-life-dairy-exports.html

Spray drying is a method of producing a dry powder from a liquid or slurry through rapid drying with hot gas.

Prolonged storage and continued exposure to temperature and moisture during transportation can lead to the browning / caking and spoilage of dairy powders. Above all, this can impact the solubility of dairy powders which, in the case of infant formula, can cause choking.