Why does foam accumulates on the surface of dal kept for long time in summer?

Foam accumulates on the surface of dal kept for a long time in summer due to the growth of bacteria and other microorganisms in warm temperatures. These organisms break down proteins and other compounds in the dal, producing gases and byproducts that create bubbles. Additionally, the heat can cause the starches in the dal to gelatinize, contributing to the foam's formation. This is often a sign of spoilage and indicates that the food is no longer safe to consume.