Creamy and smooth, butter is a delicious topping and cooking ingredient. In order to get 1 pound of butter, 10 to 11 gallons of milk must be churned. Once the fat solidifies it becomes a whitish-yellow product that must go through a long preparation process. Some recipes call for softening the butter, but leaving it out too long may cause it to spoil. Unrefrigerated butter may develop smelly bacteria that can make you sick.
Remove the lid from the butter dish. Examine the butter for obvious signs of mold, such as black spots or discoloration. If you see mold, that means the butter has turned and should be thrown away.
Smell the butter. If you detect a decomposing or cheesy smell, that means the butter is no good. Butter that smells sour, rotten or fishy should also be thrown away.
Touch the butter with your finger. The butter should be firm but slightly yielding. Butter that is mushy or feels stringy should not be eaten.
Prevent spoiling future butter products by keeping them refrigerated when not in use.
References and ResourcesShelf Life Advice; "Is There a Way to Tell if Butter Is Rancid?" Alison Soltau; June 2009
University of Guelph: Butter Manufacture
Eat Wisconsin Cheese: Butter Standards