Take You Inside the “Migration” of Food Contact Materials (FCMs)

From January 1 to April 30, 2019, the Rapid Alert System for Food and Feed (RASFF) have reported totally 47 FCMs, 38 of them are from China, accounting for 80.85%. The main reason for the failure of Chinese products is migration. Meanwhile, according to the announcement on 2018 national supervision and spot check of food-related products quality, a total of 2304 batches FCMs are checked, with 102 batches of unqualified products, accounting for 4.4%. The unqualified items mainly include: migration items such as overall migration, SML of melamine, SML (T) of formaldehyde, SML of lead (Pb), SML of cadmium (Cd), and other physical and chemical indicators such as sensory and decolor test item.

It can be found that the migration of FCMs has become a major concern. CIRS will discuss and analyze substance’s migration and migration test of FCMs.

1. Migration and migration test

Migration of FCMs

Refer to the process in which the components or ingredients of food contact materials and articles are transferred to the food in contact with them by diffusion, penetration, volatilization, release, etc. If the amount of migration exceeds the limit, it will have an impact on food safety. The migration test is an important means to study the migration of FCMs.

Migration test

It is a test which is carried out for the measurement of the amount of components in food contact materials and articles that migrate to the contacted foods or its simulants under prescribed conditions.

2. Regulations and laws of migration

Table1: Main regulations and laws of migration

Code	Name of National Standard (GB)
GB 4806.1-2016	General Safety Requirements of Food Contact Materials and Articles
GB 31604.1-2015	General Rules for Migration Test of Food Contact Materials and Articles
GB 31604.8-2016	Food Contact Materials and Articles Determination of Overall Migration Limit
GB 5009.156-2016	General Rules for the Migration Test Pre-treatment Methods of Food Contact Materials and Articles
GB 9685-2016	Standard for the Uses of Additives in Food Contact Materials and Articles

3. Introduction to the classification of migration

3.1 Classification of migration

Table 2: Classification of migration

Items	Overall Migration	Specific Migration	Total Specific Migration
Definition	The overall migration amount for all non-volatile substances from the food contact materials and articles to food simulants which in contact with them.	The migration amount of one substance or certain kind of substance from the food contact materials and articles to food or food simulants in contact with them.	The total migration amount for two or more substances from the food contact materials and articles to food or food simulants which in contact with them.
Unit	mg/dm2 or mg/kg Note: For infant food contact materials and articles, expressed as mg/kg.	mg/dm2 or mg/kg	mg/dm2 or mg/kg
Requirements	Should be in accordance with the relevant national food safety standards for overall migration limit (OML).	Should be in accordance with the relevant national food safety standards for specific migration limit (SML).	Should be in accordance with the relevant national food safety standards for total specific migration limit (SML (T)).
References	Standards for each final FCMs	1) Standards for each final FCMs; 2) GB 9685-2016; 3) Notices released by NHC;	1) Standards for each final FCMs; 2) Annex B of GB 9685-2016; 3) Notices released by NHC;
e.g.	CIRS have sorted out the corresponding requirements, as shown in Table 3.	e.g.: PE plastic added the 1,3-Bis(aminomethyl)benzene The SML of 1,3- Bis(aminomethyl)benzene in the final products should be ≤ 0.05 mg/kg according to GB 9685-2016.	e.g.: Food contact coating added formaldehyde and hexamethylenetetramine The SML(T) of those two substances in the final products should be ≤ 15mg/kg (Counted as formaldehyde) *For food contact coating added only formaldehyde or hexamethylenetetramine, the SML(T) in the final products should also be ≤ 15mg/kg (Counted as formaldehyde).

Note: If there is no requirement on “SML” and “SML (T)”, the migration of the substance should not exceed 60 mg/kg.

Table 3: Overall migration limit of FCMs

Product	Overall Migration	Limit	Test Method
Nipple	Overall Migration/(mg/kg) Water, 40℃, 24h 4% (v/v) acetic acid, 40℃, 24h 50%(v/v) ethanol, 40℃, 24h	≤ 30 ≤ 60 ≤ 60	GB 31604.8-2016
Food contact plastic materials and articles	Overall Migration/(mg/dm2)	≤ 10	GB 31604.8-2016
	Note: For the food contact plastic materials and articles contacting with infant food, the result should be converted to mg/kg according to the ratio of area to volume actually using, and the limit is ≤ 60 mg/kg.
Food contact paper, paperboard materials and articles	Overall Migration/(mg/dm2)	≤ 10	GB 31604.8-2016
	Note: Not applicable to food contact paper, paperboard materials and articles which are coated by wax on the surface. If the overall migration exceeds 10 mg/dm2, then should test the chloroform extract according to Article 5.5.2 of GB 31604.8-2016 and determine the result by the tested chloroform extract.
Coating and coating films	Overall Migration/(mg/dm2)	≤ 10	GB 31604.8-2016
	Note: For the food contact coating and coating film that will contact infant food, the result should be converted to mg/kg according to the ratio of area to volume actually using, and the limit is ≤ 60 mg/kg.
Food contact rubber materials and articles	Overall Migration/(mg/dm2)	≤ 10	GB 31604.8-2016
	Note: For the rubber materials and products that will contact with infant food, the result should be converted to mg/kg according to the ratio of area to volume actually using, and the limit is ≤ 60 mg/kg.

3.2 Others

In order to ensure the compliance of the final products, manufacturing enterprises not only need to strictly control the raw materials, but also need to investigate the possible pollutants in the final product preparation process.

For example:

1) It is favorable for the compliance evaluation of food contact plastic materials and articles to evaluate the migration of phthalate esters in food contact plastic materials and articles;

2) It is helpful to prevent the food safety risks to carry out the migration detection of bisphenol A for FCMs for infants and young children. It can be used to identify whether the product uses bisphenol A or be contaminated during the preparation process.

4. Migration test and its influence factors

The migration test is an important indicator for evaluating the safety of FCMs. It can not only judge the overall migration of FCMs, but also quantitatively calculate the amount of unreacted monomers and additives in FCMs transferred into food.

In addition to the added amount, the nature and characteristics of substance, the amount of migration is also related to the actual use of the final food contact materials and articles. There are several influence factors for migration test listed as follow. The test conditions should be selected according to the relevant requirements of GB 31604.1-2015 when carrying out the migration test.

Take food stimulant as an example: 4% (v/v) acetic acid, 10% (v/v) ethanol, 20% (v/v) ethanol, 50% (v/v) ethanol, vegetable oil or chemical solvent are the common food simulants. If the final products only contact with milk and milk drinks (including whole milk, skim or part skim milk and concentrated milk, etc.), 50% (v/v) ethanol shall be selected in accordance with GB 31604.1-2015.

5. Conclusion

Above is the analysis and summary of substance’s migration and migration test. Relevant departments should strengthen the supervision of raw materials and production processes to ensure the safety of final products. Meanwhile, enterprises should also attach great importance to the evaluation of product compliance. It is better to conduct necessary migration tests and risks monitoring based on product types to ensure the safety and compliance of food contact materials and articles.

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