The answer is yes, but with a few caveats. You can carry hard, soft, pasteurized, and unpasteurized cheeses, even those packed in brine. Butter and cultured-milk products (yogurt, sour cream) are also permitted. Just don’t forget to declare the items at the airport. On the “no” list: nonsolid cheeses like ricotta and those close in texture to heavy cream, but only from countries affected by foot-and-mouth disease. The USDA’s Animal & Plant Health Inspection Service updates restrictions based on current disease outbreaks, so double-check its website before filling your suitcase.