Parathyroid hormone (PTH) function as immunologic mediator has become interesting with the recent usage of PTH analogue (teriparatide) in the management of osteoporosis. Since the early 1980s, PTH receptors were found on most immunologic cells (neutrophils, B and T cells).
But, the refrigerator will only keep food safely cold for about four hours if unopened during a power outage, according to the USDA. A full freezer will hold the temperature for about 48 hours if full (24 hours of half full), the USDA says. Generally, if the temperature in the thermometer in the freezer reads 40 degrees Fahrenheit or below, the food is safe and can be refrozen, according to the USDA.
Much of that depends on how long your power has been out, and how much you have inside your fridge or freezer. According to the Canadian Food Inspection Agency (CFIA), a full freezer will stay frozen for 48 hours, while a half-full freezer will keep its cool for 24. A refrigerator, meanwhile, will stay keep food cold for four hours, as long as it isn't opened. Some rules of thumb to keep in mind, via CFIA: Discard any thawed food that has been at room temperature for two or more hours, and any food that has an obvious unusual colour or odour.