Is it safe? Hell yeah. As far as getting what you set out to Achieve out of the starter, no. Not with being at room temp for only 24 hours. When it was placed into the Fridge, you yeast went into a dormant phaze and has been in it since. If I were you and I wanted to brew tomorrow with that yeast, I would take the yeast out of the Fridge ASAP and let the temp of the starter to raise to room temp to let the yeasties do their thing. Personally, I wouldn't use it if my OG were over 1.050. If the OG of the Beer I was brewing was over 1.050, I would give the starter time to come up to about 68-70 degrees, then give the starter a good "swirling" to get the yeast suspended again. I would then give the yeast at least 4 days to have a good meal.