New Voluntary Standard for Food Contact Enamels Published by ISO

ISO has published a new standard, ISO 4531:2018, for food contact vitreous and porcelain enamels. This standard includes migration limits for 16 heavy metals.

Online PR News – 03-January-2019 – Geneva, Switzerland –

The International Organization for Standardization (ISO) has published a completely new voluntary standard for testing vitreous and porcelain enamels that come into contact with food.


Published in September 2018, the new standard - ISO 4531:2018 - replaces ISO 4531-1:1998 and ISO 4531-2:1998. It contains, amongst other provisions, the following requirements:

·        Defining test conditions (temperature and time) for products intended for the following applications:

o  Room temperature only

o  Hot fills

o  Grills and barbecues (short exposures)

o  High temperature applications, including cooking

·        Defining procedures for sample preparation, testing and the type of instrument for analytical measurements

·        Establishing limits for the migration of 16 heavy metals 


The sixteen heavy metals, with their migration limits (µg/l), are:

1.      Aluminum (Al) - 5000

2.      Silver (Ag) - 80

3.      Arsenic (As) - 2

4.      Barium (Ba)- 1200

5.      Cadmium (Cd) - 5

6.      Cobalt (Co) - 100

7.      Chromium (Cr) - 250

8.      Copper (Cu) - 4000

9.      Lithium (Li) - 480

10.  Manganese (Mn) - 1800

11.  Molybdenum (Mo) - 120

12.  Nickel (Ni) - 140

13.  Lead (Pb) - 10

14.  Antimony (Sb) - 40

15.  Vanadium (V) - 10

16.  Zinc (Zn) - 5000


The issuing of ISO 4531:2018 follows the publishing of Opinion No. 24/2018 by the German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung, BFR) on July 26, 2018. This report found significant quantities of aluminum, antimony, arsenic and nickel were released from certain enameled grill grates. There is currently no legally binding set of migration limits for heavy metals in these products, but the report found the levels exceeded quantities derived from acceptable exposure levels and therefore may compromise health.


The Opinion noted that grills manufactured with steel or cast iron are often coated with enamel materials to protect against corrosion and to facilitate cleaning. These enamel materials are known to contain a variety of silicates and oxides derived from metals, including aluminum, antimony, arsenic, cadmium, chromium, cobalt, iron, lead, lithium and nickel.


Stakeholders should also be aware that the European Rapid Alert System for Food and Feed portal (RASFF portal) has several notifications relating to the migration of heavy metals from food contact enameled articles.


SGS Food Contact Material Services

SGS's technical experts have extensive experience of testing materials and articles in contact with food. They ensure products meet the appropriate regulations for food contact materials and pave the way for compliance. SGS offers the full range of testing, including migration tests, along with expert advice on emerging regulations, compliance issues and documentation review. Learn more about SGS's Home Furnishings & Houseware Services. []


For further information contact:


Hingwo Tsang

Global Information and Innovation Manager

Tel:(+852) 2774 7420



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