Does open slush syrup go bad?

Yes, open slush syrup can go bad over time. Once opened, it may last for several weeks or months if stored properly in a cool, dark place and tightly sealed. However, factors like exposure to air, temperature fluctuations, and contamination can lead to spoilage, so it's best to check for any off smells, discoloration, or changes in texture before use. If in doubt, it's safer to discard it.