Left opened bottle of ketchup for 5 days, is it okay to use it?

look at fastfood diners or hot dog and burgerplaces, always out, never in a fridge, opened or not, or how the bottles are being kept in the food store, never in a fridge. the sugar content in ketchup is so high that it doesn't need to be kept in fridge according to regulation, even when it has been opened, so it's up to you, if you feel safer not using it, then bin it. What could happen though, is that it can ferment when being kept to warm for to long, and then it can mold, only you know if it has been kept in normal room teperature during these 5 days, or in a room to warm.