ARCHIVED - A Follow-up Survey of Benzene in Soft Drinks and Other Beverage Products

Background

Benzene, a known carcinogen to humans, is naturally occurring (for example, in crude oil) but is also manufactured for use in the industrial sector. Benzene is released into the air from various sources, including industrial emissions, fires, vehicle exhaust and tobacco smoke. Because benzene readily evaporates into the air from gasoline, gas stations are also a source of benzene to the air. Accidental spills and industrial waste water, for example, may introduce benzene to water and soil. Since benzene is an environmental contaminant that can be absorbed by plants and animals, food products may contain trace levels of benzene.

However, in the early 1990s, it was found that low levels of benzene can also be formed in soft drinks containing certain food preservatives and nutrient additives. It was shown that benzoate salts, used as an anti-microbial agent in certain soft drink products, can react with ascorbic acid (Vitamin C) to form benzene, especially in the presence of light and elevated temperatures. Ascorbic acid may be either naturally present from a fruit juice ingredient in the soft drink or added as an antioxidant food additive.

Shortly after the finding that benzoates and ascorbic acid can react to form benzene, Health Canada conducted a survey of benzene in fruits, fruit juices, fruit drinks, and soft drinks (Page et al., 1992). Benzene levels in the drinks were below the Canadian guideline (maximum acceptable concentration) of 5 microgram per liter (µg/L) benzene in drinking water. Benzene levels in the fruit samples were also below 5 µg/L. These levels were determined to be of very low concern to human health.

In 2005, a private laboratory in the United States informed the U.S. Food and Drug Administration (FDA) that levels of benzene in a small number of soft drinks containing benzoate salts and ascorbic acid exceeded the U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 5 µg/L for benzene in drinking water. In early 2006, Health Canada initiated a survey of benzene in soft drinks as well as in some low alcohol drinks and cocktail mixes in order to assess benzene levels in products available in Canada (Cao et al., 2007). Samples of 118 products were analyzed for benzene. Benzene was found in samples of four of the products at levels above the Canadian guideline of 5 µg/L benzene in drinking water. In these samples, average benzene concentrations ranged from 6.0 to 23.0 µg/L (2006 benzene survey results).

In order to continue to work with the beverage industry to ensure that the formation of benzene during manufacturing is eliminated from beverages sold in Canada, Health Canada was also committed in June 2006 to conduct a follow-up survey in 2007. Samples of 139 soft drinks and beverages were collected in early 2007 and analyzed for benzene. Benzene was found in samples of three of the products at levels above the Canadian guideline of 5 µg/L benzene in drinking water. Compared to the 2006 survey, the average benzene levels in most products from this survey remained low, and only a few products still contained benzene at marginally elevated levels.

Sampling Plan and Analytical Methodology for Soft Drinks and other Beverage Products

In the 2007 survey, samples of a total of 139 products were collected, of which 110 were the same products as those collected in the 2006 survey. The remaining 29 products collected in this survey were either new products or not available during the previous survey. With the exception of reformulated Kool Aid drinks surveyed in 2006 which did not contain benzoate salts, the surveyed products contained benzoate salts according to their product labels or were known to contain benzoic acid as a natural constituent (e.g., for cranberry drinks). The samples spanned a wide range of domestic and imported products, and consisted of carbonated and non-carbonated drinks, cocktail mixes, low-alcohol (0.5% alcohol by volume) drinks, and energy drinks, packaged in aluminum, plastic, or glass containers. At least three samples of each of the 139 products were purchased in April 2007 in local grocery stores in Ontario.

The samples were analyzed by an improved laboratory method based on headspace gas chromatography-mass spectrometry (GC-MS) analysis (Method for Determination of Benzene in Soft Drink).

Data Summary: Benzene Levels in Soft Drinks and other Beverage Products

Table 1(a) summarizes the levels of benzene determined in samples of ready-to-consume products, and the corresponding results from the 2006 survey for comparison. Table 1(b) summarizes the levels in concentrated products that require dilution before drinking. The average benzene levels in three of the products from different lots are shown in parallel in the tables.

In the 2007 survey, samples of three products contained benzene at levels greater than the Canadian guideline of 5 µg/L for benzene in drinking water. Only one of these three products contained an average benzene concentration above the WHO guideline for benzene in drinking water (10 µg/L). Two of these products would not be destined for consumption by children (they are mixes for alcoholic beverages).

The benzene levels found in the 2006 reformulated Kool Aid drinks ranged from not detected to 0.34 µg/L (close to the detection limit for the method used in the previous survey). Benzene was not detected in these products in the 2006 survey because the method used for sample analysis had a higher detection limit. Thus the results for Kool Aid drinks from both surveys are consistent. The previous formulations of these Kool Aid drinks have been discontinued from production, replaced by newly formulated products of the same name.

The average benzene levels in samples of the Mr & Mrs T Margarita Mix product from four different lots were 11, 17, 17, and 18 µg/L. These results are higher than the results for the same product in the 2006 survey (9.9 µg/L for the sample product purchased from a local store in Ottawa, and 2.5 µg/L for the sample product provided by the manufacturer after reformulation in 2006). However, this product was further reformulated in 2007 by removing sodium benzoate after the results were communicated to the manufacturer, and Health Canada re-tested these reformulated products in December 2007. The average benzene levels in these final samples of Mr & Mrs T Margarita Mix was 0.041 µg/L.

The average benzene level in Rose's Cocktail Infusion - cranberry twist mix was 0.09 µg/L. This is consistent with the result (not detected) for the same product provided by the producer in the 2006 survey due to the higher detection limit of the method used in 2006 survey.

The average benzene levels in A&W diet root beer products from four different lots were 9.1, 0.91, 0.06, and 0.18 µg/L, respectively, for lots 1 to lot 4. It could be determined from the lot numbers that products from lots 2-4 were produced after the product from lot 1. Given that the remaining three lots contained very low trace levels of benzene, it was therefore concluded that the one elevated lot would not have resulted from benzene in-situ formation.

Conclusions

At the time of release of the 2006 survey results, distribution of previous formulations of certain soft drinks found to have higher levels of benzene was ceased, and a voluntary reformulation of products took place. Re-evaluation of these same products in 2007 shows decisively that these new formulations have resulted in a clear reduction of benzene formation. Where required, follow-up with manufacturers has continued in order to ensure that sources of benzene formation in products surveyed in 2007 are effectively controlled. Health Canada's 2007 survey of benzene in soft drinks supports the update of its Health Risk Assessment conducted in May 2006. The 2007 health risk assessment concludes that low-dose exposure to benzene levels found in soft drinks do not pose a health risk to the general population, nor to susceptible consumers, in particular to children.

Notes for the Tables:

• "n.d." means that benzene was not detected. Where benzene was detected, confirmation of benzene identity was based on two criteria: (1) the retention time (within ±0.01 min. of the standard); (2) the ion ratios of m/z 77/78 and 51/78 (both ion ratios have to be within ±25% of the standard). Benzene was not considered to be detected if these two criteria were not met.
• "< 1" means that benzene was detected in the products, but the levels were less than the reporting limit of the GC-MS method, 1 µg/L (the reporting limit is the lowest concentration that can be reliably measured).
• "not available" means the product was not available for analysis.
• In 2006 the detection limits for method 1 and method 2 respectively were: 1.0 µg/L and 2.0 µg/L
• In 2007, the detection limit for method 2 (improved method 2) was 0.016 µg/L
• It should be noted that the absence of any particular brand from this survey means only that the brand was not included in the survey. No particular inference should be drawn from the presence or absence of any brand.
• It should be noted that differences between foods and brands do not necessarily reflect differences in exposure or potential risk that would be faced by consumers. The results shown in the table are exploratory and should not be used as indices of good product choices for consumers.

Table 1(a). Concentrations (µg/L) of benzene in ready-to-consume soft drink and other beverage products

^a results for samples from different lots

Table 1(b). Concentrations (µg/L) of benzene in concentrated soft drink and other beverage products
(These concentrated products are diluted prior to consumption)

^b results for samples from different lots
^c samples provided by the producer (Cadbury)

References

Cao, X.-L.; Casey, V.; Seaman, S.; Tague, B.; Becalski (2007) A. Determination of benzene in soft drinks and other beverages by isotope dilution headspace gas chromatography/mass spectrometry. J. AOAC International, Vol. 90, No. 2, 479-484.

Cao, X-L; Casey, V. (2008). Improved method for the determination of benzene in soft drinks at sub-ppb levels. Food Additives and Contaminants, 25(4): 401-405.

Health Canada, 2006. Health Risk Assessment – Benzene in Beverages.

Health Canada, 2006. Survey of Benzene in Soft Drinks and Other Beverage Products.

Page, BD; Conacher, HBS; Weber, D; Lacroix, G (1992) A survey of benzene in fruits and retail fruit juices, fruit drinks, and soft drinks. Journal of AOAC International, Vol. 75, No. 2, 334-340.