PACKAGING REGULATION AND MIGRATION INVESTIGATION IN CHINA

Abstract

As an important part of food safety, the safety of food packaging has received much attention from both the ordinary people and the government. Therefore the government has enhanced its supervision of the impact of packaging on the food safety. This paper reviews the laws, regulations and standards on safety of food packaging, and the migration investigation in China. Special focus is on the issues like the additives in food packaging and paper packaging. The advances in migration testing, migration model and molecular dynamics simulation on migration in China are enhanced. [PUBLICATION ABSTRACT]

Headnote

ABSTRACT

As an important part of food safety, the safety of food packaging has received much attention from both the ordinary people and the government. Therefore the government has enhanced its supervision of the impact of packaging on the food safety. This paper reviews the laws, regulations and standards on safety of food packaging, and the migration investigation in China. Special focus is on the issues like the additives in food packaging and paper packaging. The advances in migration testing, migration model and molecular dynamics simulation on migration in China are enhanced.

Key words: Regulation, migration, packaging materials, food packaging safety.

INTRODUCTION

Chinese packaging industry including packaging materials, packaging machinery and packaging printing has developed very fast. The value of the Chinese packaging industry's annual output soared from US$ 126 bn in 2008 to US$ 205 bn in 2011. Paper and plastic packaging materials, which represent over 60 percent of Chinese packaging industry's output, have become the two pillars. However, more and more food -packaging-related safety incidents like the addition of melamine in milk powder and the use of swill-cooked dirty oil for cooking have aroused concern among people. As an important part of food safety, the safety of food packaging has received much attention from both the ordinary people and the government. Therefore the government has enhanced its supervision of the impact of packaging on the food safety. This paper reviews the laws, regulations and standards on safety of food packaging, and also the migration investigation in China.

REGULATIONS ON SAFETY OF FOOD PACKAGING

The most recent incident is the toxic capsules issue. China Central Television (CCTV] reported on April 15 that 13 commonly prescribed drugs had been packed into capsules made from industrial gelatin, which contains a much greater amount of chromium than edible gelatin. This issue caused great panic and fury among people. Although there are requirements set both by industrial standard and Chinese Pharmacopoeia, the crazy pursuit of profits made the enterprises ignore these. On April 19th China's State Food and Drug Administration (SFDA) issued an emergency notice to suspend the selling and consumption of the 13 medications produced by nine pharmaceutical companies. SFDA announced on April 27th excessive chromium was found in 74 batches of capsules produced by 15 enterprises. The Ministry of Public Security has arrested 9 people, detained 45 suspects, closed 10 illegal industrial gelatin and gel-capsule factories, and confiscated tonnes of industrial gelatin. The incident of toxic capsules reflects many problems of the supervision and administration mechanism, which is worthy to be noticed by the society.

In the aspect of law on safety of food and food packaging, "Food Safety Law of the People's Republic of China" has been implemented from 2009. This law contains safety standard of food packaging products, the legal duty and the punishment of violation of the law of the following people: the users and producers of food packaging products, the producers of new food packaging products and the users, producers and operators of imported food packaging products. Amendment 8 to the Criminal Law has been implemented last year, and criminals committing food safety related crimes face severer penalty.

The report of food safety information is included in the basic public health service items of China. "Schedule for Key Workings on Food Safety in 201 1" mentioned that behaviour of producing food and food packaging materials failing to meet the safety standards would be investigated and treated. "Provisions on the Administration of Permit for New Varieties of Food Related Products" and "Declaration and Acceptance Provision of New Food-related Product Varieties" were issued last year. The food related products include food packaging materials, containers and additives. We would like to mention that for some new food-related product varieties, migration amount and/or residue amount, estimated dietary exposure and its estimation method should be provided.

Recent years the additives in food containers and packaging materials have caused great concern, especially Bisphenol A (BPA) in infant milk bottles. Now in supermarkets, these bottles were taken off from the shelves. "Circular for Clearance of Food Packaging Materials" was issued in 2009. All additives and resins that have not been listed on Chinese food packaging materials standards but used in China shall be reported to Ministry of Health (MOH). "Explanation of Clearance of Food Packaging Materials" and "Requirements on Application Material of Clearance of Food Packaging Materials" issued in 2010 gave the data requirement for clearance of food contact materials. "Letter on Seeking Public Opinions of Additives and Resins to Be Approved for Food Packaging Materials" was issued last year. MOH has approved 196 additives and 1 16 resins. "Letter on Seeking Public Opinions of Forbidding Bisphenol A (BPA) Used in Containers for Baby Food" issued last year forbids the production and import of infant food containers such as milk bottles containing BPA. "Hygienic Standards for Uses of Additives in Food Containers and Packaging Materials" gives the principle of use of 959 varieties of the additives, allowable varieties of additives, scope of use, maximum amount, specific migration limits or maximum residue amount and other restricting requirements. A series of standards have been implemented concerning determination of toxic components in packaging materials and their migration to food simulants. In 2009, 22 national standards and 25 local standards containing specific migration limits were put into effects. At present, the migration limits are most concerned in the standards on packaging containers and materials.

Now paper packaging sector is the largest in packaging industry. Base paper and its products used for food packaging should meet the national hygienic standard. "Rules for Implementation of Production Permit of Paper Food Packaging and Containers etc." has been put into effect since 2007, which announced the first batch of paper food packaging and containers including 8 varieties for paper packaging, and 13 varieties for paper containers. The professional committees and censorships for market access of paper food packaging and containers have been set up. The enterprises can not produce the paper food packaging and containers that are not in the catalogue of the first batch. No units or person can sell or use the products without production permit.

MIGRATION INVESTIGATION IN CHINA

A. Research on migration

Both 10th and 11th Five National Science and Technology Support Projects funded the research of the migration and the control of toxic components in food contacting materials. A large number of universities and academic institutes in China have been researching on it, among which Packaging Engineering Institute of Jinan University has outstanding performance. In 2009, Packaging Engineering Institute of Jinan University obtained the project "research on control technology of harmful substances in food packaging materials" funded by the 1 1th Five National Science and Technology Support Project.

B. Migration testing

Table 1 is the summary of papers on migration testing published in recent years by Chinese researchers, mostly in international academic journals. It includes the contaminants, packaging materials, the destination (various food or simulant), sample pretreatment method, detection method and the specific migration limit (SML) of some contaminants. The contaminants include solvent residue like benzene, toluene and raw material like melamine. Primary aromatic amine (PAA) is the reaction product between the packaging materials and water-based food. Most contaminants investigated are additives in plastics, paper or can, and phthalates are most frequently studied. For example, the migration of DBP, DEHP, DOP and ATBC from paper packaging ink to milk powder was studied. Offset printing was used to simulate the real situation. Antimicrobials are added for active packaging. The release of these five antimicrobials (eugenol, isoeugenol, thymol, cinnamaldehyde and vanillin) from soy protein isolate films into olive oil followed the Arrhenius equation and their activation energies were calculated. Manufacturers of plastic food containers incorporate nanosilver to exploit its antimicrobial properties. But nanosilver is dangerous to organisms due to its dimension. The potential risks from its migration are preventing scientists and the public from fully supporting the advancement of nanosilver technology.

After solvent extraction with or without SPE cartridges, the samples are commonly determined by methods like LC or GC coupled with various detectors depending on the properties of the contaminants. Chromatography coupled with tandem mass spectrometry can provide higher sensitivity and selectivity. Based on the indirect headspace gas chromatographic method (HS-GC), a volume ratio method was developed to measure the partition coefficient of organic contaminants between paper base packaging materials and air by Huang et al. (2008).

C. Migration model

Since the interaction between food contact materials and foodstuffs is foreseeable physical processes, one can build mathematical models to predict the migration processes instead of doing experiments during a period of time. Modelling is an attractive tool since fast computer is available.

The migration processes are mainly divided into three categories: Fick's diffusion, Fick's diffusion plus reaction and Non-Fickian processes. Most models are based on Fick's diffusion. Generally speaking, there are two methods to solve the Fick's diffusion equation to obtain the analytical solution. One is based on Crank method using method of separation of variables, and another on the error function using method of Laplace transform. It is difficult to obtain the analytical solution while studying the migration of contaminants in the multilayer composite materials. Therefore the numerical methods such as finite difference method and finite element method to get the numerical results of the migration are used. Based on the numerical method, we have developed corresponding software analyzing system "MigraSoft 2006". This system can analyze the migration process in up to 5 layer composite packaging materials.

As we know, diffusion coefficient and partition coefficient are the two most important parameters influencing the migration process. The system can be used to investigate the changes of the migration process when the diffusion coefficient and partition coefficient vary.

D. Molecular dynamics simulation on migration

The molecular dynamics (MD) simulation technology has been used widely to investigate many engineering problems at the molecular level. It can also be used to investigate in detail the process, the mechanism and the influencing factors of the migration at the molecular level.

Understanding the diffusion of migrants in polyethylene terephthalate and calculation of diffusion coefficients are very important for the migration research. The migrations of 13 kinds of small molecules with molecular weights ranging from 32 to 339 g.mol·1 from PET were investigated with using MD simulation. Fig. 1 shows the simulated morphology of free volume voids of 6 substances in polymer models at two temperatures by Wang et al. (2010).

The comparison among simulated, predicted and experimental diffusion coefficients as a function of molecular weight and as a function of temperature were obtained, and the simulated ones are closer to the experimental results than the predicted ones.

To evaluate the influence of types of polypropylene material on the migration behavior and to reveal the diffusion mechanism, the migration of limonene through three types of polypropylene materials (PP-H, PP-B, and PP-R) were studied by using MD simulation. The diffusion trajectories of the limonene molecules in PP-H, PP-B and PP-R were obtained by Wang et al. (201 1), and shown in Fig. 2. The movement of limonene in PP-R is more active than that in PP-H and PP-B.

From the study of the migration of 13 substances from PET, and the migration of the same substance through PP with different structures, we are quite positive about the potential use of molecular dynamic simulation in the study of the migration.

ACKNOWLEDGEMENTS

The authors acknowledge the financial support of this study by projects 2 1 27706 1 and 21077045 supported by the National Natural Science Foundation of China, project 2009BADB9B04-0 1 supported by the National Key Technology R&D Program, project 07005952 supported by the Nature Science Foundation of Guangdong Province, project PB20051013 supported by the Science and Technology Foundation of Zhuhai, and project supported by Key Laboratory of Product Packaging and Logistics of Guangdong Higher Education Institutes.

References

REFERENCES

Huang, C-X., Wang, Z. -W., IJu, Y., Wang, S.-F. 2008. Headspace gas chromatographic method for the determination of partition coefficient of organic surrogates between paperboard packaging materials and air. Chinese Journal of Analytical Chemistry 36: 1396-1398.

Wang, Z. -W., Wang, R-L., Hu, C-Y. 2010. Molecular dynamics simulation on diffusion of 13 kinds of small molecules in polyethylene terephthalate. Packaging Technology and Science 23: 457-469.

Wang, Z. -W., Wang, P. -L., Hu, C-Y. 201 1. Investigation in influence of types of polypropylene material on diffusion by using molecular dynamics simulation. Packaging Technology and Science, article first published online: 24 Oct 201 1, DOI: 10.1002/pts.983.