The main qualities of an aluminium cooking utensil are lightness and high thermal conductivity.
Metal containers are normally produced by the cold plastic deformation (pressing or drawing) of flat discs. Considering that moulding is a much easier and more economical technique if the mechanical strength of the metal is lower and its ductility is higher, aluminium is a metal that offers the best combination of moulding performance, mechanical strength and conductivity, all of which are indispensable for a good kitchen utensil.
In particular, the ability to conduct heat is an essential requirement when it comes to finding a good cooking utensil. A container with good conductivity:
consequently reduces the risk of localised overheating and burning.
Better conductivity, in fact, means higher thermal efficiency
and a quicker increase and uniform distribution of temperature.
Today, uncoated aluminium is the metal most commonly used
in the food-service sector.
The aspect that limits its use in the home is the ease with which food sticks to the bottom of the cookware, and its nonsuitability for use in a dishwasher.
The quality of an aluminium utensil is directly proportional to its thickness.
A considerable thickness ensures a uniform distribution of heat by reducing the probability of the formation of so-called “hot spots” or areas that overheat.
A considerable thickness also guarantees that the bottom remains flat, which must always be calibrated to prevent the bottom from becoming convex during cooking.
In fact, aluminium expands during heating. If the bottom of the utensil is flat and not concave before heating, it is highly likely to become convex, resulting in stability problems and limited heat transmission when cooking on glass ceramic hobs.
Therefore, aluminium is not suitable for use on induction hobs.
In order to be suitable for use with induction heat sources it
must be combined with a ferromagnetic metal.
Usually, ferritic stainless steel plates are applied to the bottoms of aluminium utensils using mechanical joining, braze welding or deposition techniques.
The aluminium used in uncoated cooking utensils is always obtained through plastic transformation and never through die casting.
The extensive number of experiments carried out in recent
years has led the National Institute of Health to be among
the leading centres on testing the migration of aluminium
into foods. This institute has taken a definitive position on
the health characteristics of aluminium in cooking utensils,
dispelling any possible doubts among those responsible for
controlling health-related issues. The National Institute of
Health wanted to verify if, and to what extent, aluminium
could be considered suitable for contact with food within the
time prescribed by law, but even before, to verify its eventual
migration to food.
The results of tests on food have revealed that the consumption of a normal meal for an average Italian could lead to contamination of less than 1 ppm (part per million) per meal, in a hypothetical scenario where everything is prepared in aluminium containers. This confirmed the finding that only prolonged contact, at room temperature or in a nonrefrigerated setting, with acidic foods should be avoided, as a precaution.
This experiment was subsequently translated into an explicit
rule to ensure peace of mind for the consumer: Decree no. 76
of 18 April 2007 published in Italian Official Gazette no. 141
of 20 June 2007.
In particular, aluminium used to manufacture materials and items intended to come into contact with food must meet the purity criteria established in the annexes of the aforementioned regulation.
The conditions of use of aluminium containers are as follows:
a) brief contact: less than 24 hours at any temperature;
b) prolonged contact: longer than 24 hours at refrigerated temperatures;
c) prolonged contact: longer than 24 hours at room temperature only for foods listed in annex IV.
Following a request from the European Commission, the Panel
on Food Additives, Flavourings, Processing Aids and Food
Contact Materials (AFC) was asked to provide a scientific
opinion on the safety of aluminium from all sources of dietary
intake. In the event the estimated exposure for a particular
sub-group(s) is found to exceed the Provisional Tolerable
Weekly Intake, a detailed breakdown by exposure source
should be provided. The major route of exposure to aluminium
for the general population is through food.
Aluminium in drinking water represents another, minor, source of exposure.
Additional exposures may arise from the use of aluminium compounds in pharmaceuticals and consumer products. Under normal and typical conditions the contribution of migration from food contact materials would represent only a small fraction of the total dietary intake.
However, the Panel noted that in the presence of acids and salts, the use of aluminium-based pans, bowls, and foils for foods such as apple puree, rhubarb, tomato puree or salted herring could result in increased aluminium concentrations in such foods.
Also, the use of aluminium vessels and trays for convenience and fast food in might moderately increase the aluminium concentrations, especially in foods that contain tomato, different types of pickles, and vinegar. It has been suggested that aluminium is linked to the aetiology of Alzheimer’s disease and that it is associated with other degenerative diseases that affect humans. These suggestions, however, remain controversial. Based on available scientific data, the AFC panel of experts does not believe that exposure to aluminium through food poses a risk for the onset of Alzheimer’s disease.
In this regard, the German Federal Institute for Risk Assessment (BfR), commenting a new study conducted on the possible cause-effect relationships between the intake of aluminium and Alzheimer’s disease, has concluded that this relationship has not been proven in a scientific way: “so far no causal relationship has been proven scientifically between elevated aluminium up-take from foods including drinking water, medicinal products or cosmetics and Alzheimer’s disease. ”
All the materials mentioned in this guide are regulated by the following laws, directives and guidelines that can be downloaded from the following links of the EFSA (European Food Safety Authority) and the COE (Council of Europe): downloadable at the following link:EFSA COE Download the pdf guide