By Pritii Tam Wai Yin
Product packaging is essentially what gives us the opportunity to store and conserve consumption resources i.e our food and water, for long periods of time, and is one of the crux and necessities of survival and civilisation. This can vary from leaves and hollowed logs, to the more sophisticated ceramic pottery and woven baskets. Food storage has evolved since towards ceramic, polymer and metal-based containers in the current ages. With the boom of the Bayer and Hall-Heroult processes that brought us aluminium as a much cheaper alternative, as well as bringing about ease of design and manufacture, the understanding of aluminium exposure in the food and beverage conservation and logistics environment becomes imminent in our consumer-based world.
The why’s of aluminium packaging
Aluminium as a packaging material, whether it exists as a standalone aluminium foil meant for high-temperature use (i.e. baking, packing hot food), or paired with multiple layers of other relatively inert materials (i.e. Tetrapak with extremely thin layers of polyethylene, aluminium foil and paperboard), is extremely useful in terms of food safety and avoidance of bacterial contamination, as well as storage as part of our resource and logistics management of food in the long term basis (i.e. the zombie apocalypse scenario). However, the part and parcel of storing food and beverages in any types of container involves also the potential migration of chemical components from the packaging itself towards consumable products. The potential health effects of the exposure of aluminium via this pathway has garnered a lot more attention from regulators and the general public.
What it means to be in acceptable limits of our maximum exposure to chemicals
The types of packaging influences the different pathways of chemical exposure. For instance, glass, though recognised generally as a safe container for holding food by the FDS, has been assessed to contain 26 to 57 times more lead compared to the Polyethylene terephthalate (PET) plastic-based water bottles from the investigations of the Institute of Environmental Geochemistry of the University of Heidelberg in Germany. The leaching of glass containers into the drinking water was at the levels of below 761 ng/L, well below the maximum allowance of lead exposure within drinking water (10µg/L in EU and Canada, and 15µ/L in USA (Claudio, 2012)).
Currently the aluminium tolerable intake levels, as determined from the 74th meeting of the Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives (JEFCA, 2011) reports provisional tolerable weekly intake (PTWI) of 2 mg/kg body weight that was established based on a no-observed-adverse-effect level (NOAEL) of 30 mg/kg body weight per day and application of a safety factor of 100. The PTWI applies to all aluminium compounds in food. Yokel (2012) reports the potential typical exposure and elevated exposure levels of aluminium within our daily life, with our typical exposures derived mostly from naturally occurring and additives contained within food and non-water beverages. As it can be observed from the table below, the calculated intake of potential Al intake daily is 100 times below NOAEL levels from the typical exposure of Al from food (naturally occuring, additives, food preparation and storage). Elevated exposures of Al, though still lower than the NOAEL levels, are at a factor of 10 times instead, with higher exposure towards dialysis patients and paediatric care.
The potential impact of aluminium toxicity
Aluminium toxicity due to exposure in elevated levels leave groups that are impaired or with negligible renal function with much greater risk as they are unable to excrete aluminium from the system. One of the few known impacts of aluminium particularly targets the use of dialysis, as it can produce encephalophaty (i.e. dialysis dementia), associated with elevated aluminium levels within the brain (Cooke and Gould, 1991) . This was due to aluminium-based phosphate binders that form an insoluble form within the intestines that was meant to facilitate phosphate elimination from the body. In addition, Yokel (2012) also explains that exposure to aluminium levels lower than aluminium-induced encephalopathy levels could also induce low turnover bone disease or microcytic anemia. Alzheimer’s disease has been a subject to many debates with regards to aluminium's role as a potential environmental contributor towards neuronal degeneration. However, the published research to date that has studied the controversial adverse effect of aluminium have suggested that the risk, if any, are extremely low. There is no concrete evidence of aluminium-based adverse health effects, as the issue itself has not been adequately assessed, though it is confirmed that those with inhibited renal performance are at the greatest risk of aluminium-induced toxicity (Yokel, 2012). More ongoing research towards this issue is a necessary step in the future for towards understanding consumer interaction with aluminium as a whole.
Claudio, L. (2012). Our Food: Packaging & Public Health. Environmental Health Perspectives. 120.
Cooke, K. and Gould, M. H. (1991). "The health effects of aluminium--a review." Journal of the Royal Society of Health vol. 111(5): 163-8.
JEFCA (2011). Joint FAO/WHO Expert Committee On Food Additives: Summary and Conclusions. Summary report of the seventy-fourth meeting of JECFA Rome.
Yokel, R. A. (2012). Aluminum in Food – The Nature and Contribution of Food Additives. InTech. Y. El-Samragy.