When there is not enough time to thaw frozen foods, or you’re simply in a hurry, just remember: it is safe to cook foods from the frozen state. The cooking will take approximately 50% longer than the recommended time for fully thawed or fresh meat and poultry.
To sum up, thawing in room temperature, or in hot water, are not safe methods.
Also, never thaw foods in a garage, basement, car, dishwasher or plastic garbage bag; out on the kitchen counter, outdoors or on the porch. These methods can leave your foods unsafe to eat. Might as well cooking without thawing.
And the safe methods are thawing in refrigerator or in cold/ ice water, and thawing in a microwave or metal trays.
Except thawing in refrigerator, when the food has been thawed by the other methods, it is not recommended to refreeze it. Because freezing cannot kill the bacteria, it will only let the bacteria enter the hibernation state. After thawing, as the temperature rises, the bacteria will multiply in large numbers. Putting them in the freezer again will not freeze the bacteria that have grown. So, we should take as much frozen food as we want.