Metals and alloys

Are various metal containers imported from China safe to use and what  risks can the metal containers involve?

It is almost impossible to draw any general conclusion as to the composition and quality of Chinese steel cookware. The importer is responsible for the quality of the imported steel containers and is obliged to have the quality inspected before importation. If necessary, a request may be made directly to the importer for further information on an individual product.

With metal containers, the greatest risk is the possibility of heavy metals from them migrating into food. Stainless steel has become the standard for contact with food. It is relatively stable and compact in composition and is therefore one of the safest food contact materials. However, the quality of steel containers made in different countries may vary as there is currently no material-specific legislation at EU level for metals that would determine their composition and the amounts of metals migrating.

Often metal detachment can be detected even with the naked eye and it is advisable to keep the senses alert when using containers. In the case of acidic foods, particular attention should be paid to the quality of the metal container, because acidic food may dissolve the metals from a container made of inferior quality steel.

What quality of brass is suitable for the food industry?

There are many different types of metal alloys sold under the term brass. The suitability of brass for applications used in contact with food must be assessed through the quality and quantity of the individual metals it contains and their potential transfer (migration) into food. It is important that the manufacturer of the brass is able to provide a declaration of compliance for the material in accordance with Regulation (EU) 1935/2004 indicating that the quantities of the components migrating from the material concerned are not such that they constitute a hazard to human health, that they would not change the composition of the food to make it undesirable or have an adverse effect on the organoleptic characteristics of the food. The declaration of compliance  should include information about the metals contained in brass and information about their possible migration into food.

To assess the aforementioned characteristics, the metals in the brass must be examined  in the light of the limits for the individual metals laid down in food legislation. The general rule can be considered as being that the raw materials of the brass should not contain any lead or cadmium whatsoever. The Finnish national Heavy Metals Decision 268/1992 (KTM) regulates the migration of heavy metals (nickel, cadmium, lead and chromium) from all contact materials and these limits must be confirmed by examination. In the case of other metals, the limits can be reviewed on the basis of the Technical Guide of Council of Europe Resolution CM/Res(2013)9 on metals and alloys used in food contact materials. The guide contains the limits laid down for different metals in the EU area, as well as information on the harmfulness and applications of each metal. Similarly, there is a Nordic (Norden) guide on metals and alloys that can also be used as a guideline for assessing the migration concentrations and harmfulness of metals.

What are the requirements for stainless steel coming into contact with food?

Stainless steel used as contact material must meet the requirements of Framework Regulation (EU) 1935/2004, but there is no material-specific legislation for it.

A manufacturer of steel for use as a contact material must demonstrate the safety of the material and its suitability for contact with food. Safety references that may be used include French or Italian national legislation on metals or, for example, stainless steel standards. The composition of stainless steels is largely standardised. Certain standard grades of steel are used for the manufacture of articles coming into contact with food. Standard steel grades can be found, for example, in the following publication of the European Steel Association: http://www.worldstainless.org/Files/issf/non-image-files/PDF/Euro_Inox/TheSafeChoice_EN.pdf

Can aluminium containers, such as saucepans, be used in cooking? What happens when aluminium comes into contact with a steel implement?

Yes, they can. However, they should not be used in the preparation of acidic foods (e.g. berries and juices). In addition, steel tools (e.g. ladles, whisks) must not be used when aluminium saucepans, for example, are used, since aluminium and steel form a so-called electric couple, which results in the more active (anodic) metal corroding the less active (cathodic) metal due to the voltage difference created between them. The greater the difference in voltage between the metals, the greater the corrosion of the less active (cathodic) metal. Also, contact of the surfaces of the items is important, because the smaller the less resistant metal is in relation to the more active metal, the higher the corrosion rate. Moist food acts as an electrically conductive substance due to its liquid content. Steel is made from iron and chromium (often also nickel and molybdenum), among other things. Based on the galvanic series of metals, it can be considered that aluminium is a less active metal than iron and chromium and so it begins to dissolve.

Is galvanised sheet suitable for direct contact with food e.g. in spinning honey?

This cannot be generalised. It is possible that honey dissolves zinc, which is quite easily soluble. Questions are also raised by what is meant by a sheet, is it made from stainless steel or is it a so-called a tin sheet containing a tin-lead alloy? These differ substantially from each other in terms of chemical resistance and non-reactivity. Food business operators must always ensure the suitability for food contact of the materials and articles they use case by case.

An operator has itself manufactured (from stainless steel) equipment for fish processing (tables, holding basins, etc.). What documents are required for the metal?

The operator must request a document indicating regulatory compliance, - such as a declaration of compliance or a certificate of suitability for contact with food - indicating that the steel complies with the requirements of Framework Regulation (EU) 1935/2004. In addition, the document must include a mention of the basis for the above assurance, i.e. safety reference(s) and what kind of contact with food the metal is suitable for.

Metals used in food contact materials must fulfil the general requirements of Regulation (EU) 1935/2004, i.e. their components must not, under foreseeable conditions, migrate into food in quantities that would render the food hazardous to human health, inappropriately alter the composition of the food or impair its organoleptic characteristics. There is currently no material-specific special legislation for metals, so safety references must be obtained elsewhere. The Council of Europe has drawn up a recommendation on metals and related technical guidance on the requirements for metals and alloys coming into contact with food and this, for example, may be used as a safety reference. EU law applies the principle of mutual recognition of non-harmonised contact materials. This means that in Finland, the national material-specific legislation of another EU country can be accepted as a safety reference. At least France and Italy have national legislation on metals. In addition, there are standards at least for stainless steel and aluminium suitable for contact with food, which can be used to ensure the suitability of the metal for contact with food. Information on standard steel grades can be found, for example, in the following publication of the European Steel Association: http://www.worldstainless.org/Files/issf/non-image-files/PDF/Euro_Inox/TheSafeChoice_EN.pdf

Pages 20-25 of the publication deal with stainless steels coming into contact with food. Under the NSF standard, stainless steels coming into contact with food should be AISI 200, AISI 300 or AISI 400 series alloy designations. The standard for aluminium is EN 602: 2007.

Page last updated 4/24/2019