Not frying foods for long enough

When frying potato chips, you can tell when they're done by looking for a color change. However, in the case of other foods, particularly those that are unpleasant or even dangerous when consumed raw, such as chicken, an external golden brown is insufficient. Instead, keep track of how long the food has been in the fryer to ensure it's fully cooked before removing it.

Taste of Home provides approximate cooking times for commonly fried foods such as fish, chicken, and doughnuts. Timing is, of course, only a guideline, especially since the temperature of the fryer oil can drop when a large amount of cold food is added. As a secondary method of determining when food is done, the outlet provides the internal temperature you should aim for, which you can check with a probe thermometer before removing the rest of the batch from the oil.