How Hot?Cooking and marinating on timeAll these marinades decrease natural carcinogens, or heterocyclic amines (HCA), found in meat by up to 87 percent since they're a barrier against the high heat. Grill beef at least 375 degrees. “The USDA says to cook poultry within two days of marinating, and beef within five days,” says La Puma. “If you marinate long, the food will either be so tender it's falling apart, or tough as nails, depending on how much acid (i.e., vinegar, lemon, wine, other) you use.”To keep grilling safe, just a dunk is necessary. With the right mixture, the longer you marinate, the stronger the flavor. La Puma recommends marinating meats in a pie plate or stainless steel bowl in the fridge to keep bacteria down.