Tag: plastics

Despite the ban on single-use plastics, their presence remains prevalent in retail stores. In grocery stores, for example, you’ll notice pre-cut fruits, vegetables, baked pastries, prepared food and bulk snacks all packaged in lightweight, clear plastic containers. When you look for produce, you’ll notice a roll of thin, translucent disposable plastic bags for fruits and vegetables. Although the ban on plastic shopping bags at the retail level has had a significant effect, more work needs to be done to address plastic pollution effectively

We depend on retailers and the Government to implement and enforce the necessary changes required to reduce plastic consumption nationally. Unfortunately, the lack of coordination between the various levels of government and the retail industry hampers progress. To protect themselves from the harmful effects of plastic on their health and the environment, eco-conscious consumers must educate themselves about the chemical composition of plastic materials.

Below is an overview of the chemical composition of the most popular plastic products used for food containers in your grocery stores.

Polyethylene Terephthalate or PET Plastic Containers

Polyethylene Terephthalate or PET are not familiar words we would use in our everyday conversation. Yet, this material is present in our everyday life. PET, as it is known to many, is made from polymerized ethylene glycol (C₂H₄(OH)₂) and terephthalic acid (C₆H₄(CO₂H)₂. Because of its durability, lightweight and resistance to moisture, it is the preferred plastic material for wet and dry food. It is the plastic container or jar used for sauces, condiments, microwavable meals, snack foods, single-serving yogurt cups, and liquid coffee creamers. 

The two primary chemicals in PET are ethylene glycol and terephthalic acid. Ethylene glycol is a key ingredient in antifreeze and is used in various industrial processes. It can be toxic if ingested, inhaled, or absorbed through the skin in significant amounts. Though ethylene glycol is used in the production of PET, it is not present in the final product. During polymerization, ethylene glycol reacts with terephthalic acid to form PET, which means that the final PET material does not contain free ethylene glycol. As long as PET containers are used according to guidelines, it is deemed to be safe according to the FDA (US Food and Drug Administration) and EFSA (European Food Safety Authority).

Although PET plastics are declared to be relatively safe, extreme heat such as microwaving, can make the plastic less stable and will leak chemical substances which is harmful to our health. If PET containers can produce harmful effects to our health in certain conditions, its end-of-life presence in the environment also poses the same risks. 

PET has a recycling code of #1 which is highly recyclable and can be cleaned, shredded and processed into new PET products. But only about 30 – 40% of containers made of PET are recycled in the US and while Canada only recycles 33%. The recycling rates vary by region depending on the recycling infrastructure in place and the adoption of recycling practices. 

High-Density Polyethylene (HDPE) Plastic Containers

For sturdy containers, high density polyethylene (HDPE) is the ideal plastic material. HDPE is commonly used for dairy products like yogurts, milk and creams, juices and large water bottles, frozen meals, bottled condiments and sauces. HDPE’s chemical composition is polymerized ethylene (C₂H₄). Due to its food-grade compliance, durability and strength, chemical resistance to acids and alkalis found in food products, higher temperature tolerance to hot and cold and clarity options (translucent to opaque finishes), it is an attractive and cost-effective option for food manufacturers.

HDPE is a relatively simple type of polymer based on the polymerization of ethylene. The polymer chains in HDPE are linear and closely packed, which contributes to its high density and strength but to enhance its stability further, UV stabilizers and antioxidants are added to extend the life of the container. 

Under low temperatures, HDPE is stable and food safe. It remains flexible and durable making it ideal for use in refrigerated and frozen environments. It does not become brittle and break in frozen temperature. However, HDPE has a melting point between 120°C to 180°C (248°F to 356°F) and when exposed to heat, HDPE may release small amounts of chemicals, though generally not a significant concern under normal conditions. However, long-term exposure or high levels of certain additives could pose risks, which is why regulatory agencies carefully control their use.

HDPE has a recycling code #2 recyclable but not biodegradable. Approximately 30% to 35% of HDPE containers are recycled in the US, 33% is recycled in Canada, and 40% are recycled in Europe. The recycling rate is influenced by factors such as local recycling infrastructure, consumer participation, and market demand for recycled materials. Efforts to improve recycling rates continue through better education, infrastructure, and technology.

Polypropylene (PP) Plastic Containers

Polypropylene is widely used for food packaging such as microwavable frozen food, yogurt cups, sauce bottles, deli containers, and flexible pouches for soup mixes, pet food and other dry goods. It chemical composition is made from polymerized propylene (C₃H₆). Due to its heat resistance, chemical resistance and durability, it’s a popular choice for grocery food products.

PP is chemically inert, which means it does not react with food or beverages under normal conditions which minimizes the risk of leaching harmful substances into the food. It’s resistant to many chemicals, including acids, bases, and oils, making it suitable for a wide range of food products.

Polypropylene has a high melting point (around 160-170°C or 320-338°F), which allows it to withstand microwave and dishwasher temperatures without deforming. It’s durable and can withstand impact and stress, providing a reliable option for packaging and storing food. Many polypropylene containers are designed to be microwave and dishwasher safe, making them convenient for everyday use.

Polypropylene is labeled with recycling code #5, indicating that it is recyclable. But while polypropylene is recyclable, it is not biodegradable. Containers made of PP do contribute to environmental waste and can exist in our landfills for centuries.

Polycarbonate (PC) Plastic Containers

Polycarbonate (PC) is typically used for soft drink or water bottles and restaurant containers. It’s considered an ideal material for plastic due to its clarity, durability and impact resistance. The primary monomers used to produce polycarbonate are bisphenol A (BPA) and phosgene. The polymerization of these monomers forms the polycarbonate polymer. The chemical formula of BPA is C₁₈H₁₈O₂. BPA is a key component in the production of polycarbonate and provides the backbone of the polymer chain. The chemical formula of phosgene is COCl₂. Phosgene is used to introduce carbonate groups into the polymer chain.

Polycarbonate plastics often contain bisphenol A (BPA), a chemical that has been associated with health concerns. As a result, many manufacturers have shifted to BPA-free alternatives for food containers. When using polycarbonate containers, it is important to check if they are labeled as BPA-free. Regulatory agencies, such as the FDA, monitor the safety of materials used in food contact applications. 

Polycarbonate has a softening point of around 230°C to 250°C (446°F to 482°F) and starts to decompose around 300°C to 350°C (572°F to 662°F). This decomposition releases gasses such as carbon dioxide and can result in a reduction in material strength cause warping or loss of mechanical properties.

Polycarbonate is classified under the recycling code #7, which is a general category for various plastics. Recycling polycarbonate can be challenging due to its specific processing requirements and concerns related to BPA. 

The recycling rate for polycarbonate in the U.S. is estimated to be around 1% to 2%, in Canada at around 2 – 3% and in Europe around 5 – 10%. These low recycling rates are due to the lack of facilities that have specific sorting and processing techniques to recycle polycarbonate.

Minimizing Plastics’ Environmental and Health Impact

Although industry regulators (FDA, Health Canada, EFSA) claim plastics are safe for food storage, exposure to extreme conditions can cause these materials to degrade and leak harmful chemicals into our food. In addition, its non-biodegradable property poses environmental harm. While we wait for the industry to find safer food packaging alternatives, consumers can take actions to minimize plastic use in our environment and retail stores.

Firstly, adopt recycling as best you can to extend the life of plastic containers and reduce landfill waste. Secondly, shop at stores that offer bulk goods with minimal packaging or those that use more sustainable packaging options. Thirdly, choose products packaged in glass jars instead of plastic containers. 

We still have work to do to improve the recycling rate for recyclable products. But in the meantime, focusing on what we can control can make a positive difference.