Can I check the sealed pork breast when I fly to America?

Strictly speaking, it is impossible. On the plane, you must fill out a form stating that you have no food or plants and sign it. When you leave the US Customs, the immigration officer will ask you again when checking your documents: "Do you have any contraband, such as food and plants?" After that, you can pick up your luggage, and then it depends on your luck. China tourists whose luggage has been picked up will be randomly selected. If you are picked up, all your luggage will be turned over. Of course, I went out when I didn't get it.