Cream cheese is made from a combination of cream and milk, and is not matured or hardened, as are other cheeses. Instead, it is slightly firmed by the introduction of lactic acid. Frequently, less expensive brands will add stabilizers like guar gum to get the necessary firmness, because the high fat content of the milk products is prone to separating. Some feel that using stabilizers in cream cheese is cheating and they will only eat cream cheese made the "old-fashioned" way. If made without stabilizers, cream cheese may be more crumbly than spreadable, and it has a relatively short shelf life, even when kept refrigerated.