No, it is not safe to cook a frozen roast in a pressure cooker without thawing it first. Cooking a frozen roast in a pressure cooker can result in uneven cooking, and the center of the roast may not reach a safe temperature within a reasonable cooking time, which can lead to foodborne illness.
There are two primary reasons why you should avoid cooking frozen meat, including roasts, in a pressure cooker:
Uneven Cooking: When cooking a frozen roast in a pressure cooker, the outer layers may cook faster than the frozen center. This can result in an undercooked center and an overcooked exterior, compromising both the taste and texture of the roast.
Food Safety Concerns: To ensure food safety, it is essential to cook meat, especially large cuts like roasts, to a safe internal temperature to kill any harmful bacteria that may be present. Cooking from frozen can significantly extend the cooking time, increasing the risk of bacterial growth on the surface of the meat.
To safely cook a roast in a pressure cooker, it is recommended to thaw the roast completely before cooking. Thawing can be done in the refrigerator over several hours or overnight, or you can use the defrost setting on your microwave. Once the roast is fully thawed, you can proceed with your pressure cooker recipe as usual, ensuring that the roast reaches a safe internal temperature of at least 145°F (63°C) for beef and pork, and 165°F (74°C) for poultry.
If you're short on time, you can also consider using other faster thawing methods like the cold-water method, where you submerge the roast in a leak-proof plastic bag and place it in cold water, changing the water every 30 minutes until the roast is thawed. But remember never to cook the roast from frozen in the pressure cooker for safety reasons.