Source: The Great Interpretation of Dreams (Ibn Sirin)
Spoiled or sour milk (curdled) in a dream indicates unlawful money, sustenance with hardship and fatigue, or a corrupt nature.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Spoiled milk indicates worry, grief, and illness.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Spoiled milk is interpreted as unlawful money or worry.