Water acts as a solvent for many items, and a pure water freezes at 0° C. When any solute item like salt, alcohol, or glucose is mixed in pure water, then this solution is called solute-solvent mixture and it has a lower freezing point that of pure water i.e. below 0° C.
An example is sea-water which remains liquid at temperatures below 32 °F or 0 °C.
Therefore, a solution of glucose in water has a freezing point that is less than 0 °C.