I'm pretty sure sodium benzoate is bad, not sure about citric acid .
Anyway, the other day my dad told me something interesting, he used to sell aloe vera but then he found out that aloe vera is only potent when it's fresh. No matter what they do to it, "new technology" etc. the bottled stuff will not have the effects that are touted for aloe vera. Be it externally or internally. That's not to say that it wouldn't do anything. I would recommend you buy an aloe vera plant or two, and use that fresh if you wish to have its therapeutic effects.