Belgian beverage study shows need for more benzene research

Tag : acidity regulator
Benzene is a carcinogenic compound that is known to be formed when twocommon ingredients in soft drinks - sodium benzoate (a preservative) and ascorbic acid (vitamin C) - are usedtogether. When placed in acidic conditions, sodium benzoate breaksdown into benzoic acid.

While the beverage industry says significant efforts have been madeto curb the formation of the carcinogen in products, theresearchers in the new study say that their findings "indicate that the problem of benzene formation in soft drinks isstill a valid topic".

What is more, their analysis suggests that there may be otherfactors at play besides sodium benzoate and ascorbic acid, such as packaging decisions, and (although requiring further study) shelf life andstorage conditions.

The researchers, from the Belgian Federal Agency for the Safety ofthe Food Chain, used a headspace gas chromatographic-massspectrometric method to measure the amount of benzene in 134samples of soft drinks sold on the Belgian market.

They used this method because the samples do not require muchpreparation. They were just shaken gentle for 30 seconds to mixthem up and, in the case of carbonated beverages, degassed with theapplication of sound for about a minute and a half, until all thebubbles had disappeared.

Ten samples were found to have benzene levels above the Europeanlimit for drinking water, 1μg L -1 .

The drinking water level is the most commonly used reference, sinceno legal limit for beverages in soft drinks exists. However anaction level of benzene in soft drinks of 10μg L -1 has been suggested by the Standing Committee on the Food Chain andAnimal Health of DG Health and Consumer Protection.

One of the soft drinks samples included in this study exceeded thisproposed action level. The study does not reveal the identity ofthe product.

The team found that 33 per cent contained no detectable benzene atall, and 47 per cent contained only trace amounts below thequantification level for the method.

A four-way ANOVA test was used to test the role of differentfactors in benzene formation. In addition to the benzoic acid(sodium benzoate) and ascorbic acid, they also looked at acidityregulators (such as citric acid and phosphoric acid) and packagingmaterial.

They observed that the interaction between the benzoic acid and theacidity regulator, and ascorbic acid and the acidity regulator,also seemed to play a role. However only one sample analyses usedbenzoic acid and ascorbic acid but no acidity regulator, sostatistical evaluation was not possible.

A statistical analysis was made against benzene levels and type ofpackaging. "This test indicates that significantly higher concentrations ofbenzene were detected in soft drinks sold in plastic bottles thanin canned soft drinks or in those commercialised in glass bottles," wrote the study authors.

In addition, 12 of the samples were found to actually be of thesame soft drink, all produced by the same manufacturer and allbottled in glass. However, they had different batch numbers andwere sampled by different people, on different days and indifferent locations.

The results were wide ranging, but that with the highest benzenecontent was seen to be the one closest to the expiration date.However, not enough data were available to say for sure thatexpiration date has a part to play.

"Other factors, such as storage conditions, may also play a roleand need to be further investigated," said the researchers.

Source

Journal of Agricultural and Food Chemistry
DOI: 10.1021/jf072580q
"Monitoring the benzene contents in soft drinks using headspace gaschromatography-mass spectrometry: A survey of the situation on theBelgian market"
Authors: Christof Van Poucke, Christ'l Detavernier, Jan VanBocxlaer, Rudi Vermeylen, Carlos Van Peteghem.