Feb 22, 2006
Benzene Soda
Sodium benzoate (E211) is a public health issue that has been bubbling for fifteen years and could soon come to a head and have the fizzy drinks industry frothing at the mouth.
Sodium benzoate is a preservative added to carbonated beverages, but those drinks that also have added citric or ascorbic acid (vitamin C, E300) can be susceptible to the formation of benzene as a degradation product. At least that’s the theory.
The US Food & Drugs Administration (FDA) was aware of this issue in the 1990s and alerted manufacturers who were then meant to introduce a “quick fix” to prevent this carcinogenic degradant from forming in amounts above safety levels. However, there have been hundreds of new susceptible beverages brought to market the world over since by smaller manufacturers as well as the well-known ones and seemingly the benzene message has been lost in the intervening time.
Germany’s food watchdog, BfR, and the UK’s Food Standards Agency are currently testing drinks to see whether benzene levels are above WHO recommendations. Other countries are also on the alert. The renewed concern follows the FDA’s re-opening of an investigation, closed for 15 years, into benzene in soft drinks.
You can read more details of this at industry newsletter Beverage Daily
Some studies have shown that levels of benzene are present at five times the WHO’s limit for drinking water contamination and can occur in bottled soft drinks exposed to heat and light especially.
In acid conditions, benzoate is converted to benzoic acid (the active antimicrobial form, benzoate is added as a preservative for a reason after all) and it is thought that it interacts with hydroxyl radicals released by the ascorbic acid (better known as vitamin C) reaction with iron or copper ions in the water. These hydroxyl can decarboxylate benzoic acid, releasing carbon dioxide and leaving benzene behind. But, at what rates this occurs is not clear.
Moreover, leaving out the ascorbic or citric acid from soft drinks would be the simple solution and avoiding benzoate as a preservative in foods that contain these acids naturally would offer an end to the “problem”.
However, the issue brings to the fore once again the issue of acceptable risk. Sodium benzoate is present in soft drinks only in very small amounts and even if degradation were complete, the risk to someone drinking it is tiny. To have the same exposure as lab animals used to demonstrate carcinogenicity would mean a person having to drink 10,000 bottles of benzoate-containing soda.
Still, such minor details will not stop the media from jumping on this as the next big scare story despite the fact that it’s been around for years as public chemophobia.
Anonymous, I have absolutely no idea what point you are trying to make. Your original reference to chocolate and cocaine is bizarre, no one was under the illusion that cocoa and coca are the same! I removed your offensive reference to the causes of blindness. But, I would like to understand what pertinence this item has to the truly worrying trend for drinking gallons of carbonated acidic beverages. I’m not at all worried about trace amounts of benzene in these drinks, it is the relatively vast quantities of sugar, the phosphoric or carbonic acid content and the effect long-term consumption could have on teeth, obesity, and bone density that concerns me.
Remember when mom said don’t eat dirt – the latest on that was it develops a stronger immune system so it is ok, no harm in eating dirt. Coffee will stunt growth, not so said scientists. Eating or drinking chocolate is as addictive as cocaine…
Well, it’s not the testing for it that would be too dangerous. If you have a sample containing benzene, then it represents an intrinsic risk factor regardless of whether you’re testing it or not, but that risk depends on actual dose.
I’d recommend finding an alternative science fair project: http://www.sciencebase.com/scince_fair_projects_online.html
Of course, you must consider dose and possible routes of exposure when discussing any sample as to whether it’s dangerous or not. Benzene is an aromatic hydrocarbon occurring naturally in crude oil and many other substances and is present in petrol (gas) because of this and because it is formed during oil refining. The quantities in soda and other fizzy drinks mentioned in this post are tiny compared to the levels in petrol.
As such, you’re going to struggle to do a science fair project to determine benzene in soda, without proper analytical lab equipment. On the other hand, you would be wise not to take a sample of petroleum into class to test even though the levels of benzene might be more accessible. Regardless of the long-term risks of cancer from exposure to benzene, it smells strongly, is poisonous, and flammable. Steer clear.
I need to do a science fair project and I’m looking for a procedure for testing benzene levels. Is there some place I should look to find it? or is it something that is extremely dangerous and expensive to test for?
Sophia, thank you for pointing that out. That’s my concern too. The drink you mentioned is very very popular among ppl from HK. It’s such a great homeotherapy (I think) to suppress the growth of a cold!
Thanks to Sciencebase for the prompt reply that definitely relieves my worry! :)