The regulatory survey is one of a number sparked off worldwide in February this year after the US Food and Drug Administration (FSA) first revealed to BeverageDaily.com, a sister publication to FoodProductionDaily-USA.com, that it had found some drinks containing benzene above the legal limit for water in the US.
Test results revealed last week by the Health Canada found that in more than 80 per cent of the 118 products tested, benzene was either not detected or found at levels below the lowest concentration that can be reliably measured. Four drinks were found that had levels above the Canadian guideline of five micrograms per litre for benzene in drinking water.
In response to the survey and public concerns about the presence of benzene in soft drinks, Health Canada said it is working with the beverage association to reduce the formation of the chemical in their products. Some of the products will be reformulated to reduced the presence of the chemical. It said the levels found in the survey, even those above the standard,
The BeverageDaily.com investigation confirmed that both the US food regulator and the American soft drinks association had known about the issue for 15 years, but had keep it under wraps in the hope that industry would solve the problem.
The tests are part of regulatory moves worldwide to discover how widespread a problem the chemical poses to human health. The testing has led to product recalls and legal suits in the US against major manufacturers, including Coca-Cola, PepsiCo, Kraft and Cadbury Schweppes.
Benzene is a known human carcinogen and can form in drinks during their shelf-life when vitamin C in the form of ascorbic acid combines with either sodium benzoate or potassium benzoate, which are common preservatives used to prevent bacteria growth in drinks. Its formation is also dependent on on the soft drink's composition and storage conditions.
In Canada, the health regulator found the highest concentrations of the chemical in a Kool-Aid Jammers 10 tropical punch, made by Kraft Canada. The product had benzene levels were 4.5 times above Canada's drinking-water standard. Another Kool-Aid flavour tested for benzene at nearly three times the standard. Mott's Margarita Mix was found at almost twice above the limit. Rose's Cocktail Infusion, sold by Cadbury Schweppes Canada, had benzene levels 20 per cent above the drinking-water standard.
A Kraft spokesman told the Globe & Mail newspaper that the company would not be withdrawing existing stocks of the Kool-Aid products, citing a statement from Health Canada that "exposure to benzene through these beverages does not pose a health concern".
There is no legislative limit for benzene in soft drinks, but many regulators opt for the World Health Organization's (WHO) limit for drinking water of 10 parts per billion (ppb).
The testing worldwide was sparked off after the US FDA in mid-February reported the results of tests showing that some soft drinks were contaminated with benzene at levels above the 10ppb recommendation.
The FDA report led to widespread media attention, because exposure of humans to benzene has been associated with leukaemia and other blood disorders.
The problem had originally been identified in the early 1990s, when it was demonstrated in laboratory trials that benzene could be produced in soft drinks containing sodium benzoate (E211) and ascorbic acid (Vitamin C) (E300) through interaction of these two permitted food additives.
The formation of benzene in soft drinks is often exacerbated when the beverages are stored for extended periods at elevated temperatures, according to the report by the FSAI. Light can also promote benzene formation. Evidence indicates that sweeteners, such as sugar, high fructose corn or starch syrup, can delay the reaction as the phenomenon seems most noticeable in diet beverages.
There is also some evidence to suggest that ethylene diamine tetraacetic acid (EDTA), which is used as a sequestrant, may mitigate the reaction by complexing metal ions that may act as catalysts.
"Trace amounts of benzene were first found in soft drinks in the early 1990s," Health Canada said. " At that time, Health Canada and other regulatory agencies, including the United States Food and Drug Administration, worked with the soft drink industry to determine how the benzene was formed and what production practices were required to remedy the situation. This experience has shown that by controlling processing conditions and formulation, trace amounts of benzene can be virtually eliminated."
Benzene is a solvent that was widely used in the past and is still used in a wide variety of industries, including as an additive in unleaded petrol. It is found in air, particularly in urban areas, as a result of emissions from motor vehicle exhaust , service stations and industrial emissions. The UK Department of Health estimates that people in an urban area may be exposed to about 400 ppb of benzene per day just by breathing traffic fumes.
This results in an exposure level which is equivalent to drinking about 40 litres of water containing approximately 10 ppb benzene per litre, according to calculations by the Irish food safety authority.