I have some raw beetroot I bought about a week ago, having stored them at room temperature since. It's the first time I bought it raw, and I'm unsure whether it's still edible. 

It is already soft, and when I cut it, it smells... Well, different than I expected. It's not a *rotten* smell as such, but it's nothing like the sweet beet-rooty smell I know from the pre-packaged, pre-boiled supermarket variety.

How can I tell whether it's still safe to eat?