Yes, milk will spoil faster when left out of the fridge compared to when it is refrigerated. Milk is a perishable food product that contains nutrients and moisture, making it an ideal environment for bacterial growth.
When milk is left at room temperature, the bacteria present in the milk can multiply rapidly, especially in warm or humid conditions. As the bacteria multiply, they consume the nutrients in the milk and produce byproducts, such as acids and gases, that cause the milk to spoil. The spoilage process leads to changes in the taste, smell, and texture of the milk, making it sour, curdled, and eventually unsafe to consume.
On the other hand, refrigeration slows down bacterial growth and helps preserve the quality and freshness of milk for a longer time. The cold temperature in the fridge inhibits the growth of most bacteria, extending the shelf life of the milk.
To ensure the safety and quality of milk, it's essential to store it in the refrigerator at or below 40°F (4°C) and promptly return it to the fridge after use. If milk has been left out at room temperature for more than two hours (or one hour in hot weather conditions), it is best to discard it to avoid the risk of foodborne illness. Always follow proper food safety guidelines to prevent spoilage and maintain the freshness of perishable foods like milk.