A new Danish scientific study has revealed higher-than-expected levels of antimony in a range of packaged fruit-juice drinks and fruit-based cordials. However, the discovery of elevated levels in juices in three different packaging materials means the source of contamination remains unclear.
The research team, from the University of Copenhagen in Denmark, measured the concentration of antimony in more than 42 different brands of fruit drinks packaged in PET, Tetra Pak laminates and glass.
The researchers found that eight of the 42 samples tested (in diluted concentrations in the case of cordials) exceeded the levels permitted in drinking water within the European Union. In the worst case, the level was exceeded by a factor of 2.7.
Antimony trioxide is widely used as a catalyst in production of PET resin and can be present at levels up to 0.035 percent of antimony in the finished polymer, according to European Food Safety Authority documents. It is also used as a synergistic flame retardant.
Antimony trioxide is classified as a Category B2 carcinogen by the International Agency for Research on Cancer, based on induced lung tumors in rodents under chronic exposure. High-level exposure to metallic antimony is known to affect the skin, heart, eyes and lungs.
In 2004, EFSA set a limit of 40 micrograms per kilogram for antimony in foodstuffs. The established European Commission safe limit for drinking water has been set at 5 micrograms per liter, according to the report authors. The U.S. Environmental Protection Agency has a drinking water limit of 6 micrograms per liter, while the World Health Organization's limit is 20 micrograms per liter.
Previous studies to determine the extent of migration of the metal into water packaged in PET bottles have typically found levels of less than 1 microgram per liter. In this latest study, published in the Journal of Environmental Monitoring, levels of up to 13.6 micrograms per liter were measured.
The researchers, however, found no clear link between the amount of antimony in the beverage and the material it was packaged in. The drink with the highest measured antimony level was packaged in a glass bottle, while the other seven samples that exceeded EU drinking water limits were packaged in Tetra Pak and PET containers.
“When analyzing all the samples as one data set, no obvious correlations could be established between antimony concentration and expiration date or any chemical properties,” said the researchers.
However, analysis of several different packs of one specific brand were said to find an association between antimony level and both the age of the sample and the sugar content.
The researchers speculate that the higher levels of antimony in the older samples may be accounted for by leaching from the packaging material. However, they acknowledge that antimony also could have found its way into the drinks during the production process, either in an ingredient or from processing equipment, and say further research is required.
“Such a mixed origin will make it harder to draw conclusions about the source,” the report authors said in their conclusion. “Further studies are warranted.”
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