IPA: //ʌnˈsaʊərd//
KK: /ʌnˈsaʊərd/
Not having a sour taste or smell; fresh or unspoiled.
The milk was unsoured and perfect for baking.
Unsoured → It is formed from "un-" (meaning not) and "soured" (from the Old English "sūrian", meaning to become sour). The word "unsoured" means not having become sour or retaining freshness.
Think of 'not' ('un-') being added to 'soured' to remember that 'unsoured' means something that has not turned sour.