Well, when the temperature of a food item increases the bacteria levels grow. So, If you refreeze something that has warmed up/melted there will be more bacteria in that particular food. It could make you sick. Also, refreezing melted ice cream will create ice crystals that will ruin its taste and the texture will be different. It won't taste the same at all.
oh haha... well then it would be the bacteria in it... bacteria like.. goes to sleep (kinda) when its cold, like they are dormant, so when it cools the bacteria are awkake and like, start eating it and stuff xP so it wouldnt be safe to eat..
Ice cream shouldn't really be refrozen because it contains milk and cream that can grow bacteria at hot temperatures. I dont think you should refreeze anything that's already been thawed out. It taste nasty afterwards anyways :/
cuz when icecream melts it turns into a liquid, and then when the liquid freezes, it just turns into ice.. so you would need to add oxygen to it, while its freezing to make it like.. fluffy.. :P
Ahha, I mean like, it's supposed to be unsafe? Like double-reheating chicken or something. I don't know o.O