This is from Wiki:
“The International Programme on Chemical Safety found no adverse effects in humans at doses of 647-825 mg/kg of body weight per day.”
Now, how much is in soda?
From another site:
“Sodium benzoate has been the subject of extensive experimentation: it has been tested in longitudinal and short-term feeding experiements in man, dogs, and rats. In one experiment in Germany, four generations of rats were continuously exposed to 0.05 or 1 percent sodium benzoate in their diet. Scientists did not observe any harmful effects on growth, life span, or internal organs. No tumors were detected. All evidence points to sodium benzoate as a safe preservative, except for rare instances of allergic reaction. “
So, I doubt that these sodas are using more than 1 percent, as that is the legally ok range it appears from the FDA.