Handling Milk Products

• One means of preventing curdling or -- more importantly -- foodborne illnesses, is through proper handling of milk-based products. Sour cream is from from cow's milk and is pasteurized, but you should refrigerate it below 40 degrees Fahrenheit. Never leave it at room temperature and always use before the 'Use-By' date, or within 7 to 10 days of the 'Sell-By' date. Use within two weeks of opening and do not freeze it.

Type of Sour Cream

• A higher fat sour cream will provide the best results because the fat in the sour cream helps prevent the milk protein from clumping together and separating the liquid. If you use low-fat sour cream for a sauce, whisk a small amount of flour or cornstarch to help prevent the sour cream from separating from the lime juice.

Ratios

• The more lime you add then the more acid you add and the more likely it is that your sour cream will curdle. If you want a strong lime taste, grate lime zest into the cream, as less acid will enter the milk product. If you are using a large amount of lime, keep it refrigerated, because the colder the sour cream is when you combine it with lime, the less likely the sour cream is to curdle. The clumping of proteins becomes stronger over time, so when you have a greater ratio of lime to sour cream, the sooner you serve the dish the better. For a strong flavor, use a ratio of up to 1 part lime juice to 2 parts sour cream and serve promptly after combining.

Heating

• Sour cream at room temperature does not have the tendency to curdle. This is perfect for lime-flavored dips or chilled side dishes, such as chipotle lime sour cream or a sour cream-based lime salad dressing. If you are creating a hot dish in which you add lime juice like a curry sauce with sour cream, add the milk product to the meal when the milk is warm -- not boiling or simmering. Do not boil the meal after you have added sour cream, or it will turn grainy.