Final answer:
Safe methods for cooling food include keeping refrigerators below 4 degrees C and freezers below -18 degrees C, using a thermometer to monitor temperatures, and correctly thawing foods. Ice and salt can be used in a double-bag method to make ice cream. For the cooling bath, a combination of water and dry ice at approximately 0°C is suitable for preserving tissue without damage.
Step-by-step explanation:
Safe Methods for Cooling Food
There are several safe methods for cooling food to prevent bacterial growth and ensure food safety. To keep the temperature optimal, the refrigerator should be set at or below 4 degrees C (40 degrees F), and a thermometer can be used to monitor this. In the case of a power outage, if the temperature remains below 40 degrees F, the food is safe, but if it exceeds that for over two hours, the food may become unsafe to consume. The freezer should be maintained below -18 degrees C (0 degrees F) to keep foods safe indefinitely, although the quality may decrease over time. When thawing frozen foods, it should not be done at room temperature, but rather in the refrigerator or by using cold water or a microwave. Once thawed, foods should be handled as fresh perishables and should not be refrozen.
An innovative method involves cooling ice cream using a double-bag method with ice and a bit of salt, which lowers the temperature and encourages the heat to transfer out of the ice cream mixture. It's also important to remember that foods meant to be served hot should remain so until served, and those meant to be cold should be refrigerated accordingly. Perishable leftovers must be refrigerated quickly to avoid the danger zone between 4 and 60 degrees C (40 and 140 degrees F), beyond which they should be disposed of after two hours.
Regarding the cooling bath scenario, Po'lah would need to use a combination of water and dry ice (solid carbon dioxide) since dry ice sublimes at -78.5°C, providing a sufficiently cold environment without freezing the severed hand. This method keeps the temperature around 0°C, ideal for preservation purposes without causing damage due to excessive cold.