What we need to know about plastics and food contact
While plastics can rightly be called the “wonder” material of the modern age, when it comes to food contact, it can be problematic. While there are many suitable options, there are also limitations. Oftentimes the choices are determined as much by the application or the food type, as much as the plastic type. Add to this the wide variety of available plastics and the equally wide variety of non-usable materials and it can be quite bewildering!
Why do we need to consider different types of plastics, anyway? This excerpt from the American Plastics Council (APC) website explains it this way:
"Copper, silver and aluminum are all metals, yet each has unique properties. You wouldn't make a car out of silver or a beer can out of copper because the properties of these metals are not chemically or physically able to create the most effective final product. Likewise, while plastics are all related, each resin has attributes that make it best suited to a particular application. Plastics make this possible because as a material family they are so versatile."
And Then There is the Government
In addition to practical concerns such as suitability, potential for out-gassing or leaching, temperature limits, etc. legal requirements and regulations must be considered. For example, the following information is from the Food Standards Agency (FSA):
Food contact material approved by the US Food and Drug Administration (FDA) does not necessarily comply with UK and EC legislation. Where there are already EU-wide rules in force in the UK, these rules must be complied with. If there are no specific rules, the general requirements laid down in the European Regulation will have to be met.
In the UK, the Food Standards Agency (FSA) does not approve products before they are allowed on the market. But it does help ensure they are safe and comply with the legal maximum levels of migration allowed for consumer protection, based on the opinions of the European Food Safety Authority.
Here comes the “Tech” bit
The regulations that govern “food safe plastics” in the UK are The Plastic Materials and Articles in Contact with Food (England) Regulations 2009, which set an overall migration limit for all food contact plastics. This limit is 10 milligrams per square decimetre of plastic surface area in general.
However, a limit of 60 milligrams per kilogram of food applies specifically in the case of containers or similar receptacles with a capacity between 0.5 and 10 litres, or which have a contact area that cannot be determined and for sealing devices such as caps, gaskets and stoppers.
The regulations also establish:
- 'positive lists’ of monomers, which are chemical compounds that can link together to form longer molecules with repeating structures (polymers); and starting substances permitted for use in the manufacture of food contact plastics
- time limits on their use
- specific migration limits
- a list of additives approved by the European Food Safety Authority (EFSA) for use in food contact plastics
Finally, the regulations establish rules for testing migration from food contact plastics and for checking compliance with the regulations.
So, What Exactly IS Food Safe Plastic?
In the US, for example, The U.S. Food & Drug Administration (FDA) requires that plastics used in food packaging be of greater purity than plastics used for non-food packaging. This is what’s commonly referred to as “food grade” plastic.
Food grade plastic does not contain dyes or recycled plastic deemed harmful to humans. However, this does not mean that food grade plastic cannot contain recycled plastic. The FDA, as well as the FSA in the UK, has detailed regulations concerning recycled plastics in food packaging.
Another aspect of defining food grade plastic is in matching the appropriate type of plastic to the food in question. Foods that are highly acidic, or that contain alcohol or fats, can leach plastic additives from the packaging or container into the food.
Interestingly, the issue of food grade plastic is significant for consumers because of health concerns and for those who store or stockpile foodstuffs either for emergencies or because of the remoteness of where they live.
What Works as Food Safe Plastic?
A comprehensive list of food safe/food grade plastics would include:
- Natural grade Nylon 6 & 6.6 (without additives)
- Polyethylene in grade 300 – 500
- Polyester (PET)
And What Should NOT Be Used…
There are some plastics that one might avoid as they may leach or have hazardous ingredients. And some plastics to be avoided altogether as they are not considered “food grade” or food safe:
- Nylons with additives (such as oilon or Mos2)
- Regen (recycled) UHMWPE
- Other (including Polycarbonate and acrylic)
Latest Plastic Development
An exciting aspect of food grade plastics development is the introduction of “metal detectable” engineering plastics which help in the case of component breakage. Material additives allow detection of very small (27mm3 and bigger) particles with the use of metal detectors. In addition, materials such as Acetal are being produced in a blue colour to help with visual detection during the Quality Control stage of manufacturing.
And Finally – Playing it safe!
Ultimately, if you need a plastic that must be safe when in contact with food, steer clear of PVC, Black Nylon or other Nylons with additives, and Regen UHMWPE. For the most part, all the other plastics are generally considered safe.