Metal content in soft drinks depending on packaging and storage time

Abstract

The rising consumption of soft drinks requires evaluating packaging and storage duration, which can affect flavor, safety, and potential metal leaching into the beverage. This study analyzed the total metal content of 104 carbonated beverages in glass, PET bottles, and aluminium cans, including beverages stored five years beyond their shelf life. Beverages included flavors such as "herbal," "orange," "lemon," and "cola". Metal content was analyzed using total reflection X-ray fluorescence spectroscopy (TXRF) as well as graphite furnace atomic absorption spectroscopy (GF-AAS). Main components like phosphorus, potassium, and calcium were stable across packaging and storage times. Metals such as cobalt, copper, arsenic, strontium, silver, cadmium, mercury, and lead were below the respective detection limits and therefore of no concern. Chromium found in old orange soft drink cans exceeded drinking water limits but was below daily intake thresholds. Manganese levels were inconsistent, and iron varied by batch. Nickel levels were below drinking water standards and zinc levels were low across all drinks. Aluminium levels varied significantly, lowest in PET bottles and highest in cans, with glass bottles showing intermediate levels. Fresh cola in 0.15 L cans contained a mean aluminium level of 1510 ± 236 µg/L, contributing 8.82 % of the tolerable weekly intake (TWI) for a 60 kg person when consuming 0.5 L daily. Herbal soft drink in cans reached 7630 ± 8640 µg/L aluminium. A clear and significant rise in aluminium content was observable in all canned beverages over time, pointing to a significant dissolution from the packing material over time.