Will milk spoil if you leave it out one night?

Milk is a highly perishable food and will spoil if left out overnight at room temperature. Harmful bacteria can grow rapidly in milk at temperatures between 40 °F and 140 °F, potentially leading to foodborne illnesses. Spoiled milk may develop an off odor, taste sour, and show visible signs of spoilage such as curdling or separation. To ensure food safety, it is recommended to always refrigerate perishable foods like milk within two hours of purchase and discard any milk left out overnight.