In general, it is not recommended to refreeze melted ice cream. When ice cream melts, the ice crystals break down, and the structure of the ice cream changes. If you refreeze it, the texture and taste may be negatively affected. The ice cream can become grainy, icy, and lose its creamy consistency.
Additionally, each time you allow ice cream to melt and then refreeze it, you increase the risk of bacterial growth and spoilage. Bacteria can multiply rapidly at temperatures above 40°F (4°C), and although freezing can slow down bacterial growth, it won't eliminate it entirely. Therefore, it's best to avoid refreezing melted ice cream to ensure its quality and safety.
If your ice cream has melted slightly, you can put it in the refrigerator for a short time to firm it up a bit before putting it back in the freezer. However, if it has fully melted or has been sitting at room temperature for an extended period, it's better to discard it to avoid any potential food safety issues.
To prevent ice cream from melting and refreezing in the future, try to minimize the time the ice cream spends outside the freezer. Serve it quickly and then promptly return it to the freezer to maintain its quality.