What is one factor that negatively affects the quality of frying oil?

Excessive heat is a critical factor that negatively affects the quality of frying oil. When oil is subjected to temperatures that are higher than its smoke point, it undergoes a series of chemical changes. These changes can lead to the breakdown of the oil, resulting in the formation of harmful compounds, off-flavors, and unpleasant odors. High temperatures can also cause the oil to oxidize more rapidly, decreasing its lifespan and making it less safe for consumption.

In contrast, maintaining correct temperatures helps ensure that the oil remains stable and effective for frying. Regular oil changes mitigate any buildup of food particles and contaminants, while low food particles can prolong the oil's usability. Hence, it's crucial to monitor the frying oil temperature to maintain its quality and safety for cooking.