My grandson is very allergic to this additive which I have noticed appears in many foods and drinks and even in toilet products etc. What is it and is it a 'dangerous additive' apart from the allergic reaction I mentioned?
It's a preservative. The problem widely publicised lately is that when it's combined with ascorbic acid (vitamin C) in foodstuffs, it breaks down and produces benzine - a carcinogen. You're probably aware that some drinks have been recalled in the UK recently for that reason. See more here
Sodium Benzoate has been found to react with vitamin c to produce a known carcinogen. I've started avoiding all products (especially shampoos) and foodstuffs containing the benzoate