Guidelines for using recycled plastics in food packaging: Considerations for secondary recycling processes

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• Source control
• Use limitations
• Recycling process efficiency for removing chemical contaminants
• Estimating exposure to potential chemical contaminants

Source control

The recycling process involves collection, sorting, reclamation and fabrication of finished products. Recyclers are expected to develop a comprehensive source control program to monitor collection and sorting. An appropriate source control may include:

• limiting the source of collection to food contact or food-safe plastics where possible (for example, only polystyrene cups, trays used to package food)
• using sorting procedures that limit the plastic resin type
• using sorting procedures that reprocess only a single characteristic container (for example, PET water bottles)
• implementing inspection systems to detect and reject containers that may contain potential hazardous or non-food appropriate substances
• documenting and maintaining records and quality specifications of all sources of recycled materials, from related batch numbers through to production lots of finished products

It's important that the recycler monitors and applies proper quality specifications for the types of plastics in the feedstock (that is, materials to be recycled). For all reasons detailed previously, recycled material won't be considered suitable for food contact use when the recycler has little or no control or oversight of the plastic materials to be recycled.

Use limitations

Due to the permeable nature of plastics, residual chemicals may remain in the recycled materials and migrate into food. The main concern associated with the use of materials produced by secondary recycling processes is related to the presence of certain substances in the feedstock such as:

• non-food grade additives (for example, colourants, UV light stabilizers, antistatic agents, fillers, impact modifiers, etc.), which may be present in non-food containers used in the recycling feedstock. As the secondary recycling process isn't designed to remove all the additives incorporated into the polymer matrix, these substances will remain in the polymer and consequently, the containers produced from PCR materials may not comply with the existing food contact regulations. This concern may be mitigated by developing sorting procedures that result in reprocessing of only food contact containers or by using the recycled plastic behind an effective barrier preventing migration of those additives into food.

• food-grade additives present in food containers used in the feedstock intended for specific food packaging applications.

  Even if all the incoming PCR materials contained only food-grade additives, the additives may not be appropriate for the types of food that could be packaged in it, or conditions of use of the finished packaging product (for example, a lipophilic plasticizer that is acceptable for use in contact with aqueous food under refrigeration temperatures could not be incorporated into packaging intended for use at high-temperatures with fatty foods). This concern may be mitigated by developing a sorting procedure that results in reprocessing of only a single characteristic container (for example, PET water bottles) or limiting the conditions of use of the finished recycled packaging (for example, 'use at room temperature') or food type-restriction (for example, 'use with dry foods').

• external chemical contaminants that are mainly present on the surface of containers, such as:
  • household products (for example, softeners, washing detergents, shower gels, creams, shampoos) that may be stored in non-food containers (relevant in situations where the sorting procedure correctly identifies a particular type of plastic with food and non-food uses)
  • other products such as pesticides or automotive chemicals (for example, motor oil) that may have been stored by end users in food containers
  • chemicals used in the recycling process (for example, detergents) that may not be completely eliminated from the recycled plastic

The type and total amount of these additives and chemical contaminants must not cause food packaging products made using PCR material to be unsafe, and therefore out of compliance with Section B.23.001 of the Food and Drug Regulations. Recyclers, packaging manufacturers and food packers can eliminate or reduce the migration of potential chemical contaminants and additives into foods packaged in recycled plastics by applying these use limitations:

• restricting the food type (for example, using only dry foods, foods with natural protective shells, raw fruits and vegetables)
• limiting the conditions of use (temperature and time) of recycled packaging materials (for example, using at room temperature or below, or limiting the duration of food contact) in order to reduce the potential migration of chemicals
• restricting the use to secondary packaging applications for which the primary packaging effectively separates food from the secondary packaging (for example, shrink-wrap around multiple plastic bottles of soda, where the soda is primarily packaged in a bottle)
• using an effective functional barrier, using recycled plastic material as a non-food contact layer in a multilayered food package, separated from food by an effective barrier such as virgin plastic or other appropriate material such as aluminum (for example, a high barrier pouch in which the food is separated from the recycled material with aluminum foil). This means that a non-food grade recycled plastic could be used to package food as long as it's separated from food by another layer that doesn't let non-food safe chemicals migrate into food.

Recycling process efficiency for removing chemical contaminants

Recycling process efficiency refers to the ability of the recycling process to remove chemical contaminants from the recycled material. It's a critical factor in determining the safety of the use of recycled materials for food packaging applications. As stated previously, chemical contaminants may originate from plastic food containers that have been used for secondary purposes not related to food packaging, such as storing motor oil or other non-food chemicals.

Determining the efficiency of the recycling process may be measured by performing a challenge test, which is required when requesting a LONO for a mechanical recycling process. Challenge tests help to determine the potential for migration of substances from plastic into food. In the challenge test, virgin plastic (for example, in the form of flakes) is spiked with a mixture or "cocktail" of selected surrogate contaminants, which represent a worst-case scenario for common contaminants that could be introduced from the post-consumer stream. The surrogates should represent various classes of commercial chemicals available to consumers (for example, automotive fuels and oils, solvents, pesticides, toxic organic salts involving heavy metals, antifreeze, household cleaners). These surrogates should be selected based on their physical and chemical characteristics (for example, polarity, molecular weight, volatility). Recommended surrogates are listed in Table 1^{Footnote 4}.

Petitioners should perform the challenge test with, at minimum, 1 surrogate from each category where there is more than 1 recommended surrogate as set out in Table 1. Petitioners should soak flakes in this mixture at 40ºC for 2 weeks, with periodic agitation. Examples of minimum concentrations of surrogates that should be present in the cocktail are listed in Table 2. If a petitioner who plans to request a LONO from Health Canada wishes to substitute any of the above surrogates with another chemical compound, they should provide a rationale to support the proposed chemical and the concentration tested.

After the contaminants are drained and the flakes are rinsed, petitioners should determine the concentration of each surrogate that was achieved through spiking. Petitioners then subject the flakes to the recycling process. Subsequently, the petitioners analyze the flakes for residual concentrations of each contaminant to determine the efficiency of the recycling process.

This approach represents the worst-case scenario, where all materials entering the recycling process stream are assumed to be contaminated.

Once the amount of potential migration, if any, is known, then the health significance of potential exposure to these chemicals must be determined.

Additional information for recycled polyethylene terephthalate (PET)

Currently, PET is the most recycled resin used for food packaging, consistent with findings from the 2021 Environment and Climate Change report on food grade recycled resin. A comprehensive set of surrogate testing data is now available, and this knowledge has led to a refinement of surrogate test requirements for PET recycling processes.

The plastics industry in the United States has provided assurances to the U.S. Food and Drug Administration that all PET resins used to manufacture containers in the U.S. are authorized for food contact use (that is, both food and non-food PET containers in the U.S. are manufactured from food-grade resins). Thus, non-food containers, such as personal hygiene products and household cleaners, etc., are considered to be in compliance with Section 177.1315 and 177.1630, Title 21 of the U.S. Code of Federal Regulations.

In Europe, all grades of PET packaging resins sold by European manufacturers and placed on the European Union market are considered food-grade. All of these PET resins comply with Directive 2002/72/EC and its subsequent amendments. If the feedstock doesn't originate from the U.S. or Europe, the petitioner must demonstrate that the feedstock originates from plastic materials and articles that are manufactured in accordance with the legislation on plastic food contact materials and articles^{Footnote 3}.

For these guidelines, Health Canada also considers all PET resins to be food-grade. For those recyclers who include post-consumer PET containers in their feedstock, Health Canada requires the petitioners to conduct a challenge test using the minimum surrogate concentration levels listed in Table 3 with virgin PET flakes prior to subjecting them to the decontamination process. The results of this challenge test will be used to demonstrate the efficiency of the cleaning process and the ability of the recycling process to remove external contaminants.

Please note that:

• Heavy metal testing isn't required for polyethylene terephthalate (PET) as, unlike small organic molecules, metal salts do not sorb as readily into PET and the salts are more easily washed out of PET.
• Surrogate testing isn't required for recycled PET or polyethylene naphthalate (PEN) that have undergone tertiary recycling, based on determining that tertiary recycling process of PET or PEN results in the production of monomers or oligomers that are readily purified to produce a finished polymer suitable for food contact applications.

Estimating exposure to potential chemical contaminants

As stated in the previous section, residual contaminants could be carried through the recycling process and migrate into food that is in contact with the packaging. Similarly, additives present in PCR material may be carried through the recycling process and migrate into food from the finished recycled container.

Recyclers and manufacturers must ensure that the recycling process is able to prevent, remove or reduce the chemical contaminants to levels that won't harm the health of the consumer of the food packaged therein.

Without empirical data on the concentrations of chemicals that have migrated from the packaging material to food, dietary exposure can, in most cases, be estimated on the basis of the residual concentration of chemical contaminants and additives in the finished packaging article. This takes into consideration factors such as:

• food consumption
• the packaging ratio
• the density and thickness of the article
• the market share of the recycled material
• the content of the recycled material in the article

For illustrative purposes, there is a sample calculation in appendix I.

In these calculations, we normally assume a 100% migration of chemical contaminants and additives from the food contact material to food, as a worst case. For more refined estimates, extraction studies can also be conducted to identify and quantify the residual contaminants and additives that may be present in the finished product and can potentially migrate into food. These studies are usually conducted using food simulants under conditions that are comparable to the proposed end-use applications, as defined in the previous section.

For the purpose of evaluating safety from chemical substances found in food packaging materials, Health Canada has established a threshold of concern (TOC) value of 25 ng/kg bw/day, which is considered to represent an exposure below which it is unlikely that a substance would represent any more than a negligible risk via food packaging. This value is consistent with the approach used by the US Food Drug Administration^{Footnote 2Footnote 5}.

When applying the TOC, Health Canada also considers:

• read across data
• predictive modelling
• structure activity relationships
• any other relevant factors

In instances where the TOC approach is deemed not appropriate, a detailed rationale will be provided. Although the TOC is meant to be applicable for all age groups (that is, when considered on a body weight per day basis), infants and young children represent a distinct and vulnerable subpopulation and are generally considered to be more sensitive to some toxicological insults than adults^{Footnote 1}. Consequently, Health Canada may consider additional factors when assessing substances to be used in food contact applications with relevance to infants and young children in order to ensure adequate health protection.

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