Roundtable Forum: New National Standards for Food Contact Materials Bring New Challenges to Flexible Packaging Enterprises

Content organized by: Fan Junhong, Chen Zhuojun

This roundtable forum is exclusively sponsored by Henkel

With the promulgation and implementation of a series of national food safety standards, more stringent control requirements have been imposed on the food packaging industry and its upstream and downstream industrial chain (including the supply chain, enterprise chain, and value chain). The introduction of these new national standards not only tests the adaptability and innovation capabilities of every link in the industrial chain, but also highlights the social responsibility and mission that flexible packaging enterprises must undertake.

Facing these unprecedented challenges, we are not only required to deeply understand the core requirements of the standards, but also need to adopt a brand-new perspective to jointly explore how to ensure food safety while strengthening technological research and development, optimizing production processes, improving product quality, and deepening industrial chain collaboration to jointly build a healthier and sustainable packaging ecosystem, driving the packaging industry toward a healthier, safer, greener, and more environmentally friendly direction, so as to safeguard consumer food safety.

1. Guests in Attendance

Moderator: Zhao Jia, Marketing Strategy Manager, Henkel (China) Investment Co., Ltd.

Guest introductions:

① Researcher Zhu Lei, China National Center for Food Safety Risk Assessment, one of the drafters of the new national standards

② Researcher Shang Guiqin, Head of the National Food Contact Materials Testing Laboratory (Changzhou)

③ End brand representative: Cui Jianfeng, Manager of Packaging Material R&D Department, R&D Center, Want Want Group

④ Printing enterprise representative: Zhang Fenghui, R&D Director, Foshan Nanhai Lida Printing & Packaging Co., Ltd.

⑤ Senior expert in the flexible packaging industry, Mr. Chen Zhixiong

⑥ Dai Mian, Senior Manager of Product Safety and Regulatory Affairs, Asia Pacific, Henkel (China) Investment Co., Ltd.

1. Guest Q&A Session

Researcher Zhu Lei, expert from the China National Center for Food Safety Risk Assessment and one of the drafters of the new national standards

Moderator's question:

These national standards all mention a new limit requirement: total migration of primary aromatic amines ≤ 0.01 mg/kg, involving plastics, rubber, inks, adhesives, and composite food packaging bags. This includes both raw materials and final products. As standard setters, what is the significance of adding this new limited substance in this series of national standards, and in your view, what countermeasures should partners in the industrial chain take to address this control?

Ms. Zhu Lei's answer:

I. Specific requirements of the new national standards:

In the past two years, the food contact material standards system has undergone significant changes:

1. The scope of standards has been further expanded. For example, the composite material standard has expanded from the very narrow sanitary standard scope of GB 9683 that everyone was familiar with in the past to all multilayer composite materials. Similarly, the plastics standard now encompasses new materials and new products commonly used in the industry.
2. In addition, the standards have adjusted limit requirements based on risk assessment results. For example, the metal standard has revised heavy metal migration limits, and in the appendices of standards such as the plastics standard, there are changes to the limit standards for monomers and starting substances.
3. The standards cover the entire chain from raw materials, production processes to final products. For example, the plastics standard has clarified certain raw material requirements, including new requirements for starch content in starch-based plastics, starch requirements, plant-based natural material components, and metal material raw materials.

From the perspective of food safety standards, the primary responsibility is to protect consumer health, followed by promoting industry innovation and development. This is the prerequisite for formulating the new national standards.

The "Inks for Food Contact Materials and Articles" standard will be implemented on September 6, 2024. The "Adhesives for Food Contact Materials and Articles" standard will be implemented on February 8, 2025. Both standards are related to aromatic amine migration, and the standards clearly specify that the detection limit for primary aromatic amines is 0.01 mg/kg. Primary aromatic amines come from two major categories: one is intentionally added substances, originating from certain polymers or starting substances and monomers used, such as phenylenediamine-type substances, which are substances we intentionally use. For example, in the appendix of the plastics standard, for this type of intentionally used substance, we have lists and limit requirements. The other is non-intentionally added substances, mainly derived from impurities in raw materials or secondary reaction products generated during production and use.

II. How enterprises should respond:

1. Enterprises are the primary responsible parties for food safety, which is explicitly required by law. Therefore, managers must be familiar with the Food Safety Law and related laws, regulations, and the standards system, and must be familiar with their own products. For example, primary aromatic amines have limits, notes, and testing methods in our standards. You need to find the corresponding standard limits and testing methods based on your product's characteristics and properties to ensure product compliance.
2. When you discover that primary aromatic amines are truly exceeding the limit, you need to trace the source—whether it is caused by the substance being present in the raw material formulation, or by impurities in the raw material, or by the entire processing technology, such as hydrolysis caused by excess isocyanate substances coming into contact with water during the curing process. You then need to communicate with the corresponding suppliers to resolve the issue or improve the process.
3. PAA migration management requires mutual cooperation between upstream and downstream enterprises. As mentioned earlier, the substances causing it may come from raw materials or from downstream enterprises. Upstream and downstream enterprises must have transparent information transfer and mutual cooperation. Upstream enterprises must provide very appropriate guidance to downstream enterprises, and downstream enterprises must control their processes according to the upstream enterprises' formulations. Only by working together can products be reasonably planned and product safety be managed and controlled.

Researcher Shang Guiqin, Head of the National Food Contact Materials Testing Laboratory (Changzhou)

Moderator's question:

In addition to the national food safety standards for raw materials and final products, GB 31604.1-2023 and GB 31604.52-2021 (determination of migration of 29 primary aromatic amines), composite film bags come in various areas and volumes, with diverse packaging structures and contents. How can testing methods, testing bases, and judgment principles be scientifically and reasonably established to control migration risks, improve testing efficiency, and reduce testing costs?

Ms. Shang Guiqin's answer:

Any product and any indicator meeting a certain limit requirement has preconditions.

For flexible laminate packaging multilayer materials, taking primary aromatic amine migration as an example, the national food safety standards for inks and adhesives both specify the testing method, namely GB 31604.52. Regarding the relevant judgment principles, how many times the test should be conducted, and how the results should be calculated, these are all stipulated in GB 31604.1-2023, and I will not go into the details here.

The key point I want to share with everyone is how the entire supply chain, upstream and downstream, can cooperate to achieve economical and effective testing. For example, when producing a composite packaging film, there are usually two situations to consider.

Economical and effective testing methods for prepackaged foods:

1. When the use is single-purpose and follows a single one-way channel, the food contents packed have a nominal weight, the area-to-volume ratio is consistent, and the expected use conditions are also consistent—for example, the temperature and time for food to be cooked inside the bag, and whether the later shelf life is at room temperature, refrigerated, frozen, or chilled. These conditions are all single-line, and you can directly select food simulants and migration test temperature and time according to the specified rules in GB 31604.1.
2. When the expected food or food categories in contact are diversified, and the expected final use conditions are also diversified, there are also economical and effective testing methods for such diversified situations. That is, first collect all the conditions such as the types of food expected to be in contact for downstream customers, contact area/volume ratio, contact time and temperature, and then analyze according to the rules in GB 31604.1 to determine which condition is the most stringent among multiple test conditions, and test only the most stringent condition. When multiple conditions cannot be ranked, the standard also clearly states that all such conditions must be tested.

Regarding the area-to-volume ratio, as Mr. Chen from Botai introduced with corn packaging, there are large and small sizes. However, because the packaging bag's specification dimensions and inner surface area are fixed, regardless of whether you are packing a large or small corn, we would typically select the packaging with the largest area ratio and volume ratio for testing. For example, if corn ranges from 80 grams to 250 grams, we can use the 80-gram corn for the final test. The less food packed, the higher the concentration of primary aromatic amines. If it passes the test according to standard requirements when packing the minimum amount of food, then the larger the food content packed, the lower the aromatic amine concentration per unit mass ratio, and the safer it is. This is the testing logic, and our standards provide corresponding explanations for all of this.

Cui Jianfeng, Manager of Packaging Material R&D Department, R&D Center, Want Want Group

Moderator's question:

Brand owners have extended their emphasis on product safety to product packaging. Comprehensive safety and reliability of products have become an important commitment of responsible brand owners to consumers. Safe packaging materials are equally important as food safety! In response to the promulgation and implementation of the new national standards, what measures will Want Want Group take to respond?

Mr. Cui Jianfeng's answer:

As the moderator just said, safe food packaging is equally important as food safety, especially for us as a food manufacturing enterprise. Our group president has always emphasized that food quality and safety are the lifeline of an enterprise, and has consistently stressed that food safety must be given high priority and no problems can be tolerated. We fully agree that product safety and reliability are the most important commitment of a responsible brand owner to consumers.

Regarding the new version of the national standards on food safety requirements, for us as a food brand owner, we have become accustomed to this. I believe that to date, China's food safety standards are already the strictest in the world. We also anticipated long ago that all aspects related to food would eventually be subject to deepened management according to the requirements for food itself. Therefore, we have made full preparations for this. We will complete a comprehensive review of all products according to the new standards, and have our partner manufacturers complete self-inspection, and ultimately deliver a satisfactory answer to the market and consumers.

Zhang Fenghui, R&D Director, Foshan Nanhai Lida Printing & Packaging Co., Ltd.

Moderator's question:

As downstream players in the industrial chain—producers of final products, sellers, and the main subjects of testing—what major challenges do you think you currently face with the promulgation and implementation of the new national standards?

Mr. Zhang Fenghui's answer:

Facing the new national standards for food packaging safety, we will handle the response work from the following aspects:

1. Our company has many packaging products exported to different regions, including Europe, the United States, and other areas, so we have specially appointed a regulatory specialist. His responsibility is to collect and organize food regulations from various regions and countries, including the newly promulgated national standards for inks and adhesives, and then conduct strict testing and inspection according to relevant requirements.

In addition, some key customers, such as Nestlé, put forward their own very strict food safety control requirements. We will collect and organize their standards and requirements according to customer needs. Packaging production is a physical processing process, and we may not fully understand the basic properties of these materials or the toxicity of PAA. What we need to do is mainly strictly control its migration to meet customer requirements.

1. Strictly control the product quality of suppliers. For example, whether inks and adhesives contain heavy metals or primary aromatic amine components that are not permitted by national standards. We not only require suppliers to provide inspection reports, but also require them to provide composition statements and classification lists that comply with regulatory requirements, as well as written declarations that their products meet regulatory requirements.

However, a difficulty encountered here is that suppliers may be unwilling to disclose these details due to formula confidentiality or other reasons, or they themselves may not be very clear about regulatory requirements. Even if they provide a declaration, it does not necessarily mean that the materials supplied comply with regulatory requirements.

1. Strictly control the production process. We need to carefully explore what kind of process can meet the new national standard requirements—for example, by adjusting curing time and curing temperature, or using different combinations of dry lamination, solvent-free lamination, and extrusion lamination processes. Which type of process can achieve perfect control of PAA migration without increasing our additional costs? This is a new challenge for us.
2. We will provide customers with a very detailed material structure statement, telling them what film materials are used for the outer and inner layers of our packaging bags, what ink and adhesive components are in between, what hazards may arise, and what process control points are used throughout the production process to ensure food safety, and summarize all this in the form of a data table into a report to inform customers in detail.

Difficulties encountered in implementing the new national standards:

1. For example, regarding PAA migration and extraction, although there are fixed testing methods and standards, the results from different testing institutions for the same product are uneven and vary greatly. This is related to the precision of testing instruments used by the testing institutions and their grasp of testing methods. Which test result should we take as authoritative?
2. Physical hazards, biological hazards, and chemical hazards can all cause food safety problems. In addition to these, there may be other hazards. How do we discover and respond to them?

Mr. Chen Zhixiong, senior expert in the flexible packaging industry

Moderator's question:

The new national standards have brought new challenges to the packaged food industry and the industrial chain (supply chain, enterprise chain, value chain), but also new opportunities. As a senior expert in the flexible packaging industry, what are your personal views and suggestions?

Mr. Chen Zhixiong's answer:

Regarding the issue of PAA residue, I encountered it as early as 2000 when I was working at ProAmpac Group, and it has now reached a point where it must be resolved.

From a technical perspective, I would like to offer the following suggestions for your reference:

1. Develop solvent-free aromatic two-component adhesives that can rapidly attenuate PAA as soon as possible—this is critical. Adhesive suppliers with strong technical R&D capabilities are capable of solving this.
2. Why is PAA generated? In the solvent-free lamination process, low-molecular-weight aromatic isocyanates migrate and react with moisture to form carbamic acid, which decomposes into ammonia and carbon dioxide. If migrated isocyanates continue to leach out, the ammonia and the leached isocyanates continue to react to form polyurea, which becomes non-toxic. However, the leached polyurea will affect heat seal performance, and we need to increase the sealing temperature. If the PAA attenuation rate is not fast enough, it may lead to PAA residue problems.

Our front-line operators in the workshop often change the ratio of the two-component adhesive when preparing it because they consider the humidity in the workshop, adding more curing agent. Because in a high-humidity environment, part of the curing agent will be consumed, so to ensure complete crosslinking reactions, more curing agent often needs to be added, which in turn can easily cause PAA residue problems. Therefore, creating a stable constant-temperature and constant-humidity production environment is absolutely necessary. Newly designed plants are often required to complete the entire production process in an enclosed environment with controlled temperature and humidity, so that we can use the standard ratio to complete the crosslinking reaction of the adhesive and reduce the occurrence of PAA residue problems.

1. To solve PAA residue, our previous approach was to use aromatic adhesives before the barrier layer (such as aluminum foil) and aliphatic adhesives after the barrier layer. This means the barrier layer will provide a barrier effect against the migration of low-molecular-weight isocyanates in the aromatic adhesive we use. Similarly, we can consider establishing a density gradient in the sealing layer material we use (such as PE)—adding HDPE to the lamination layer of a three-layer co-extruded PE film and MDPE in the middle layer. This can also provide a certain barrier effect against the migration of low-molecular-weight isocyanates. At the same time, this treatment can also help guide the amide-type slip agents added to the PE film to migrate toward the heat seal surface, reducing migration toward the lamination surface that would affect lamination bond strength.
2. Ensuring a reasonable (appropriately extended) curing time is also a way to reduce toxic PAA residue. Our past practice was to create a humidity-increasing environment in the curing room. This plays a certain role in reducing excess NCO residue.
3. Finally, one more point. Reasonable use of appropriate lamination processes is one way of thinking to solve PAA residue. Currently, the introduction of new dry lamination equipment (semi-flexographic coating and semi-floating drying ovens) has also greatly reduced production costs and improved work efficiency. The extrusion lamination process is a lamination process with no VOC emissions and no PAA residue. These are worth considering by our technical personnel and end users!

Dai Mian, Senior Manager of Product Safety and Regulatory Affairs, Asia Pacific, Henkel (China) Investment Co., Ltd.

Moderator's question:

Regarding adhesive product safety risks, similar regulations on PAA have been promulgated in the EU, South America, and South Korea. Could you share the experience of Henkel, as a multinational adhesive manufacturer and an important part of the industrial chain, in responding to the implementation of these regulations?

Mr. Dai Mian's answer:

Various countries have regulatory requirements for PAA migration control, and the general approach is basically similar, but there are still subtle differences.

I would like to share my suggestions from three perspectives:

1. Enterprises with export orders must identify the differences and similarities among regulations in various countries. Our country's new national standard requires the total migration of primary aromatic amines, with a detection limit of 0.01 mg/kg, while European regulations, in addition to not exceeding 10 ppb, also have some special requirements. For example, the EU plastics regulation EC 10/2011 and the German BfR standard not only impose limits on total PAA migration but also impose limits on specific individual PAAs. Therefore, when testing, it is necessary to select the appropriate testing targets according to the requirements of different countries, and not make mistakes.
2. Source control of PAA. Everyone understands the principle of PAA generation, but we need to consider a question: if the MDI and TDI we purchase are pure enough, they should only produce MDA and TDA. But why, in actual situations, can PAAs of other structures often be detected? In fact, one must consider a question here: are the raw materials you purchase sufficiently pure? Commercially available TDI and MDI contain isomers, which are inseparable isomers produced during the manufacturing of TDI and MDI, and therefore will also produce corresponding PAAs. Another very important point is that the differences in reaction rates of PAA generation from different isomers are quite considerable.

Henkel has always insisted on using very high-purity raw materials and controlling curing time as much as possible. Therefore, the smaller the reaction differences, the smaller the differences in PAA generation rates, and the more guaranteed the determined curing time will be.

In addition to raw materials, formulations also affect the generation and attenuation rate of PAA. Today, our company's Manager Wang Fei introduced a rapid-attenuation PAA adhesive launched by Henkel.

1. Regarding PAA migration. We must understand that the amount of PAA generated and the amount that migrates into food are two completely different concepts. Please do not confuse them. Henkel has conducted extensive research on PAA from generation to migration into food. There are many factors affecting PAA migration. In addition to conventional factors such as raw materials, speed, types, and formulation composition, there are other key factors that also affect PAA migration. For example, temperature—when exporting to Southeast Asia or Europe and America, companies are often required to provide FDA 177.1390 and/or FDA 177.1395. This is a direct manifestation of how temperature differences affect migration risk. The difference between these two standards is that one requires temperatures above 250°F and the other requires below 250°F. Why make such a distinction? This indicates that temperature is also one of the key factors affecting PAA migration. In addition, food types, processing time, etc., are also key factors.

Finally, one more point: PAA is a very important testing item in our food safety, but it is definitely not the only item. Our GB 4806 series, GB 9685, GB 31603, GB 31604 series, and other corresponding standards on overall compliance safety, migration testing, safe production, and material quality all point our enterprises in a direction. We must not only attach importance to PAA testing but also ensure that all components we actively add to our products must be listed in the corresponding national permitted lists. If they are not on the lists, we must evaluate whether the actively added substances belong to "carcinogenic, mutagenic, or reprotoxic" substances or "nanomaterial" substances. Only when it is ensured that they do not belong to "carcinogenic, mutagenic, or reprotoxic" substances or "nanomaterial" substances, and under the premise of adopting an effective barrier layer, can we adopt the exemption principle of non-migration.

1. Audience Q&A Session

First representative's question (first question):

Different testing institutions and different times produce different PAA values. Which one should prevail?

Ms. Shang Guiqin's answer:

First of all, testing itself has errors. The more core difference is that PAA generation is a dynamic process. Packaging is sent to different institutions for testing at different times, so the different testing time points lead to different test results. If you want to compare test data from different institutions, whether for PAA or solvent residue, samples should be sent for testing at the same time point.

First representative's question (second question):

When testing migration of samples in aqueous solution, should we choose the 121°C high-temperature retort test condition or the reflux temperature test condition?

Ms. Shang Guiqin's answer:

According to the basic principle of GB 31604.1, "select the conditions that best reflect the actual situation," so the high-temperature retort condition should be selected.

Ms. Zhu Lei's answer:

First choose the high-temperature retort environment for testing. If that is not feasible, then choose the reflux temperature for testing.

Li Ming, General Manager, Guangzhou Gulian New Materials Co., Ltd.

Mr. Li's question:

The PAA of adhesives changes with curing time. For some rush orders, products that are normally cured for 72 hours are accelerated to 36 hours of curing before being sent for testing. In such cases, the results may be either compliant or non-compliant. Which test result should be used as the standard?

Ms. Zhu Lei's answer:

The specified curing time should and must be completed.

Mr. Chen Zhixiong's answer:

If conditions permit, the longer the curing, the better. This can avoid side effects, and at the same time, enterprises must assume their due social responsibility.

Third representative's question:

The outer ink layer of our company's composite film is not on the standard list, while the aluminum foil composite film has an effective aluminum barrier layer inside. In this case, can we obtain exemption and use it based on the effective barrier layer provision while ensuring the migration amount is controlled?

Ms. Shang Guiqin's answer:

This provision has preconditions. The substance to be exempted must satisfy being a "non-carcinogenic, mutagenic, or reprotoxic substance" and a "non-nanomaterial substance," and at the same time, through migration assessment, the maximum migration amount must be less than 0.01 mg/kg under all relevant application conditions.

Fourth representative's question:

Regarding food simulant testing, the provisions also state that actual contents (food) can be used for testing. If the simulant test result in migration testing is non-compliant, but the test using actual contents is compliant, can the packaging be deemed compliant?

Ms. Zhu Lei's answer:

The basic principle in the standards is to give priority recommendation to using actual contents (food) for testing. However, in actual testing, the testing mechanism for food is relatively complex, and it is also impossible to determine whether the test data is detected from the packaging or inherently present in the food itself. From a practical feasibility standpoint, using simulants is completely fine. If actual contents (food) are used for testing, there is no need to also test with simulants, and the actual contents test result shall prevail.

Xu Jialiang, Packaging Research Engineer, Sanquan Food Co., Ltd.

Mr. Xu's question:

Because PAA has relatively high reactivity, it may still change after normal curing and delivery. Is it necessary to conduct long-term testing?

Ms. Shang Guiqin's answer:

Printing enterprises or enterprises using adhesives must optimize and control their production processes. The same adhesive produced in different regions will face different production environments (different temperatures and humidity). Therefore, it is recommended that every enterprise should control based on its own adhesive usage, formulation, and local production environment, and then conduct aromatic amine monitoring. After monitoring, determine at what temperature and for how long the product should be cured before leaving the factory to ensure safety. At the same time, using the second audience member's question as an example, if testing has already indicated that the product must be cured and stored for three days, do not ignore food safety issues in order to save time.

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