"Food must be kept at a safe temperature during "the big thaw." Foods are safe indefinitely while frozen. However, as soon as food begins to defrost and become warmer than 40 °F, any bacteria that may have been present before freezing can begin to multiply.
Foods should never be thawed or even stored on the counter, or defrosted in hot water. Food left above 40 °F (unrefrigerated) is not at a safe temperature.
Even though the center of the package may still be frozen as it thaws on the counter, the outer layer of the food is in the "Danger Zone," between 40 and 140 °F at temperatures where bacteria multiply rapidly.
When defrosting frozen foods, it's best to plan ahead and thaw food in the refrigerator where food will remain at a safe, constant temperature 40 °F or below.
There are three safe ways to defrost food: in the refrigerator, in cold water, and in the microwave.
I worked in a restaurant and health and safety forbid us to defrost seafood using warm water ..... just passing on what they suggest. In the end we had to stop selling them as we didn't have the space to defrost in the fridge for hours.