Wednesday, May 24, 2006

Benzene and soda preliminary results

The US FDA has just released preliminary data on their on-going investigation of benzene in soft drinks (see previous posts here, here and here). Using a convenience sample of 100 soft drinks from retail stores in Maryland, Virginia and Michigan, they found four different drinks (eight samples items) with benzene levels above the 5 ppb drinking water standard. Crystal Light Sunrise Classic Orange led the pack with two lots with 70 - 80 ppb of benzene. Interestingly, a lot of the same drink reformulated to have less benzene came in at less than 1 ppb.

The benzene comes from a reaction between a preservative, benzoate salt (sodium or potassium) and vitamin C (ascorbic acid). Other factos such as heat and light affect benzene formation from these ingredients so it is possible to reformulate drinks to suppress benzene exposure. There was no pretense that the sampling reported yesterday was at all representative of the retail inventory or consumer choices. The results of this relatively small sample suggest that a much larger sampling effort will be needed to estimate accurately consumer exposures to benzene, a known human carcinogen. FDA goes to some lengths to say that even those products and lots found to contain high benzene do not have uniformly high levels:
These data should not be understood to be a reflection of the distribution of benzene in beverages in the US food supply. The data cover a limited number of products, a limited number of brands, and a limited geographic region. The data do not fully address the variation from one production lot of a product to another lot. For example, when additional lots of some beverage samples initially found to contain benzene levels greater than 5 ppb were analyzed, the results indicate that benzene levels can be highly variable from lot to lot. Even products from the same lot collected at different locations may have different benzene levels depending on many factors such as time at elevated temperatures and amount of light exposure during shipping, handling, and storage. (FDA)
Fair enough. Of course this also means those products and lots found to contain little benzene in this survey may turn out to have very high levels in another sample. These results were also done in the cool weather of winter and since heat and light affect benzene formation it is likely that a study done in the summer will come up with higher levels.

Benzene is found in the environment from other sources, and some like power plants or gasoline fumes cause much higher exposures. But from the public health perspective, even small exposures with small risks are significant when billions of drinks are consumer around the world (see previous posts here and subsequent linked posts; and here). Lottery tickets have a small risk of winning, too, but if enough tickets are sold, "winners" appear. And this is a lottery no one wants to win. We shouldn't be giving cancer lottery tickets with a can or bottle of soft drink.

Additional info available at the Environmental Working Group site.