In general foods can safely be refrozen if they still contain ice crystals or if the food has been at refrigerator temperature for no more than two days. If foods are completely thawed and have warmed to room temperature, they should NOT be refrozen. Discard these foods.
Refreeze meat and vegetables only if they still contain ice crystals. Texture and sometimes flavor may be affected, so use in casseroles or mixed dishes. Seafood should not be refrozen even if they have ice crystals. These foods may be cooked and then refrozen if the temperature of the food was colder than refrigerator temperature. Do NOT cook if they have warmed to room temperature. You cannot always smell or see all signs of spoilage. Unfortunately, you may not know how warm thawed food has really become, so be overly cautious and do not take chances.
Fruits lose their shape and can become mushy when thawed. They ferment when they spoil. This is not particularly dangerous, but the taste or texture can become unacceptable. Fruit can be refrozen if the taste, smell, and texture are acceptable. Using them in cooking or making sweet spreads are a good way to use these thawed fruits.
Ice cream and other products containing air do not result in an acceptable product when refrozen. Discard these.
Refreeze partially thawed foods rapidly by turning the freezer control to its coldest setting. These foods will deteriorate more rapidly and should thus be labeled as "refrozen" and use as soon as possible.