Benzene insoft drinks is of potential concern due to thecarcinogenic nature of the molecule. This contamination is apublic health concern and has caused significant outcry among environmental and health advocates. Benzene levels are regulated in drinking water nationally and internationally, and inbottled water in the United States, but only informally in soft drinks. The benzene forms fromdecarboxylation of thepreservativebenzoic acid in the presence ofascorbic acid (vitamin C) and metal ions (iron and copper) that act ascatalysts, especially under heat and light. Hot peppers naturally contain vitamin C ("nearly as much as in one orange"[1]) so the observation about soft drinks applies to pepper sauces containing sodium benzoate, likeTexas Pete.
The major cause of benzene in soft drinks is thedecarboxylation ofbenzoic acid in the presence ofascorbic acid (vitamin C, E300) orerythorbic acid (adiastereomer of ascorbic acid, E315).Benzoic acid is often added to drinks as apreservative in the form of its saltssodium benzoate (E211),potassium benzoate (E 212), orcalcium benzoate (E 213).[2]Citric acid is not thought to induce significant benzene production in combination with benzoic acid, but some evidence[which?] suggests that in the presence ofascorbic orerythorbic acid and benzoic acid, citric acid may accelerate the production of benzene.[citation needed]
The proposed mechanism begins withhydrogen abstraction by thehydroxyl radical, which itself is produced by theCu2+-catalysed reduction ofdioxygen by ascorbic acid:[2]
Other factors that affect the formation of benzene are heat and light. Storing soft drinks in warm conditions speeds up the formation of benzene.
Calcium disodiumEDTA and sugars have been shown to inhibit benzene production in soft drinks.[3]
The International Council of Beverages Associations (ICBA) has produced advice to prevent or minimize benzene formation.[4]
Various authorities have set limits on benzene content in drinking water. The following limits are given inparts per billion (ppb;μg/kg).
TheEPA andCalifornia have set public health goals for benzene of 0 ppb and 0.15 ppb.[7]
Benzene in soft drinks has to be seen in the context of other environmental exposure. Taking the worst example found to date of a soft drink containing 87.9 ppb benzene,[5] someone drinking a 350 ml (12 oz) can would ingest 31 μg (micrograms) of benzene, almost equivalent to the benzene inhaled by a motorist refilling a fuel tank for three minutes. While there are alternatives to using sodium benzoate as a preservative, the casual consumption of such a drink is unlikely to pose a significant health hazard to a particular individual (see, for example, the EPA IRIS document on benzene[8]).
The UK Food Standards Agency has stated that people would need to drink at least 20 litres (5.5 gal) per day of a drink containing benzene at 10 μg to equal the amount of benzene they would breathe from city air every day.[9] Daily personal exposure to benzene is determined by adding exposure from all sources.
In 1990, a study reported having foundbenzene in bottles ofPerrier for sale in the United States, resulting in a voluntary product recall.[12][13]
In the early 1990s, the soft drink industry initially approachedFDA with concerns aboutbenzene formation in soft drinks. Following testing, FDA asked manufacturers to voluntarily reformulate. By 1993, FDA determined that most drinks had littlebenzene contamination.[14]
In 1993, research showed how benzene can form from benzoic acid in the presence of vitamin C.[2][15]
In the summer of 1998, a number of well known soft drinks manufacturers had to withdraw large quantities of their products from sale after benzene contamination in some production plants was discovered.[16]
In November 2005, theFDA received test results conducted by private citizens that benzene was forming at low levels in several types of beverages.[17]
In December 2005,Germany's Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung) published a review of benzene's possible formation in foods and drinks.[18]
In February 2006, an unnamed formerchemist at the FDA publicly revealed thatbenzene may be created as part of a chemical reaction during production ofsoft drinks, particularly those having anorange flavor.[19] Full-scale investigations immediately started at theFood Standards Agency (UK) and inGermany to reveal exactly which amounts of benzene, if any, were present, with several other organizations awaiting their findings.[20]
TheUnited Kingdom'sFood Standards Agency released results on March 31, 2006 for 150 beverages.[10] Its results showed 43 beverages contained benzene, four of which contained levels above theWorld Health Organization drinking water standards (10ppb). These four were withdrawn from sale.[21][22]
In April 2006, theKorea Food & Drug Administration (KFDA) announced that it had detected benzene in 27 out of 30 (90%) vitamin-enriched drinks on sale inSouth Korea. It said the detected amount of benzene – ranging from 5.7 to 87.8 ppb – was not harmful to humans but advised manufacturers of beverages containing more than 10 ppb of benzene to voluntarily recall their products.[5]
TheFDA released preliminary results[17] in May 2006 for 100 beverages showing that many soft drinks contained low levels of benzene (less than 5ppb, the federal drinking water limit) while four drinks contained amounts above the standard. Two of these drinks contained amounts 15-18 times above the drinking water standard. Many of the products showed large variations in the amount of benzene they contained. The FDA stated that it is working with manufacturers to reformulate products that contain benzene above the federal drinking water standard.[citation needed]
These test results are both lower and more accurate than a previous long-term study by the FDA. In the Total Diet Study[23] that FDA conducted from 1996 - 2001 to determine the amounts ofvolatile organic compounds in various foods, FDA used ananalytical procedure that caused more benzene to form in the drinks during the test.[24][25]
TheFDA emphasized that most beverages contain levels below 5ppb and pose no risk to consumers. Furthermore, there are no standards for beverages beyond drinking andbottled water.
On 9 June 2006,Health Canada released its study results of benzene levels in beverages. Four products out of 118 had levels above the Canadian guideline of five micrograms per liter for benzene in drinking water (average range 6.0 to 23.0 μg/L). The follow-up study the next year found only three samples with marginally higher levels and concluded the average levels were quite low.[26][27]
On 24 August 2006, two soft drink manufacturers agreed to settle aclass-action lawsuit that had been filed by a group of parents in theSuperior Court of the District of Columbia. The two companies, Zone Brands Inc., maker of "BellyWashers" products, and TalkingRain Beverage Co., denied that their products were harmful, but agreed to change the ingredients in their drinks.[28]
Coca-Cola announced that it would be phasing out sodium benzoate from many of its drinks, but notFanta andSprite.[29] As of August 2012, Coca-Cola Zero andBarq's root beer still contained benzoate (added as potassium salt and sodium salt respectively).[30]
A Belgian study found thatplastic packaging may play an important role in the formation of benzene in soft drinks.[31]
