What preservative is used in butter to keep it fresh longer?

Butter is made from heavy cream that is churned (heavily shaken) repeatedly until all of the buttermilk (milk proteins) has been released and nothing is left but the fat. As it is pale, coloring is sometimes added, and it is rather flavorless until salt is blended in, which has the added benefit of being a bit of a preservative.

Asked by Leni Davenport · Last updated 5 years ago · 676.1K views · SOURCE