In the ever-evolving world of food packaging, storage, and hydroponics, the safety and quality of materials used are of paramount importance. With an array of plastics inundating the market, understanding which are safe for food contact becomes crucial for consumers and industry professionals alike. This article delves into the realm of food grade plastics, a category of materials specifically designed to be safe and non-toxic when in contact with food and water.
Which Plastics are Food Grade Safe?
The key to identifying these safe materials lies in the recycling codes embossed typically on the bottom of plastic containers. These codes, ranging from 1 to 7 within the recycling triangle, not only facilitate recycling but also provide insights into the type of plastic and its safety profile. From the commonly used PET (Polyethylene Terephthalate) to the versatility of HDPE (High-Density Polyethylene), and the concerns surrounding plastics like PVC (Polyvinyl Chloride), each number tells a story of safety, usability, and recyclability.
- PET or PETE: Polyethylene Terephthalate, abbreviated as PET or PETE, is a highly valued plastic in the food industry, recognized for its safety and versatility. Designated by the recycling triangle number 1, PET is widely used for packaging water and soft drinks, thanks to its strong, lightweight, and transparent nature. Notably, PET is renowned for its barrier properties that efficiently protect food from oxygen and moisture, extending shelf life. In addition to being food-grade safe, PET is fully recyclable, contributing to environmental sustainability efforts. Its widespread recyclability and minimal impact on taste and aroma make PET a preferred choice for food and beverage packaging.
- HDPE: Marked by the recycling triangle number 2, High-Density Polyethylene, known as HDPE, is a robust and versatile plastic extensively utilized in food packaging. Recognized for its strength, durability, and resistance to chemicals and moisture, HDPE is commonly used for milk jugs, water bottles, and cereal box liners. Its high resistance to impacts and low risk of leaching makes it a safe choice for food-grade applications. HDPE’s lightweight nature combined with its strong barrier properties effectively preserves the freshness and quality of food products. Importantly, HDPE is not only food-safe but also fully recyclable, playing a significant role in environmental conservation efforts.
- PVC: Polyvinyl Chloride, commonly known as PVC, is a type of plastic identified by the recycling triangle number 3 and is used in various applications, including food packaging. PVC is valued for its durability, flexibility, and resistance to grease, oil, and chemicals, making it suitable for cling films, oil bottles, and food wrapping. However, it’s important to note that PVC has raised health concerns due to the potential release of harmful chemicals, especially when used with hot foods or during microwaving. As a result, its use in food-related products is often carefully regulated to ensure safety. While PVC is recyclable, its recycling rate is lower compared to other plastics like PET and HDPE, partly due to these health concerns and the complexity of its recycling process.
- LDPE: Low-Density Polyethylene, known as LDPE, is a widely used plastic in the food industry, identifiable by the recycling triangle number 4. LDPE is favored for its flexibility, clarity, and chemical resistance, making it ideal for manufacturing food storage bags, squeezable bottles, and plastic wrap. Its soft texture and ability to form an effective moisture barrier are key in preserving food freshness and quality. While LDPE is considered safe for food contact, it is less commonly recycled than some other plastics, such as PET and HDPE, due to the challenges in collecting and processing thin and flexible materials. Despite this, LDPE plays a crucial role in food packaging due to its protective properties and versatility in various food storage applications.
- PP: Polypropylene, abbreviated as PP, is a popular plastic in the food packaging industry, marked by the recycling triangle number 5. Known for its high melting point, PP is ideal for containers that can withstand microwave heating, such as yogurt containers, syrup bottles, and medicine bottles. Its resistance to fatigue, strong barrier against moisture, oils, and chemicals, makes it a safe and durable choice for long-term food storage. PP is also appreciated for not leaching chemicals into food or drinks, aligning with health and safety standards. While recycling rates for PP are growing, it is less frequently recycled than plastics like PET or HDPE, but ongoing advancements in recycling technologies are improving its sustainability profile.
- PS: Polystyrene, commonly referred to as PS and identified by the recycling triangle number 6, is a plastic widely used in the food industry for products like disposable cups, plates, trays, and take-out containers. Known for its lightweight, insulating properties, and affordability, PS is particularly favored for products like foam cups and containers that need to maintain temperature. However, PS has come under scrutiny for environmental and health concerns, particularly in its foam form, due to its non-biodegradable nature and potential for leaching chemicals when in contact with hot substances. Although PS is technically recyclable, the rates of recycling for this material are relatively low due to economic and logistical challenges. As a result, many regions are considering or have already implemented bans or restrictions on certain PS products to mitigate environmental impact.
- Other: The ‘Other’ category in plastics, denoted by the recycling triangle number 7, encompasses a variety of plastics that do not fit into the traditional categories of numbers 1 through 6. This category includes innovative and less common plastics like polycarbonate (PC), bioplastics, and acrylic. Often used in applications requiring unique properties, such as certain types of baby bottles, water cooler bottles, and sports drink bottles, these plastics can vary in their safety and recyclability. While some, like bioplastics, are praised for their eco-friendliness, others, particularly polycarbonate, have raised health concerns due to the potential leaching of Bisphenol A (BPA). Recycling of ‘Other’ plastics is more challenging due to the diversity of the materials involved, often requiring specialized processes.
Plastics and Hydroponics and Aquaponics
As more and more people migrate to hydroponics and aquaponics, one of the first questions that comes up is: ‘are all of these plastics safe?’ Well, in most cases, if you’re using the chart and information above, then they typically are, but that doesn’t necessarily make them perfect. As with any product you use in ANY industry, you need to do your own homework and make that determination for yourself.
Is PVC safe to use in Hydroponics and Aquaponics?
As PVC piping is a fundamental component in several aquaponic and hydroponic systems, it’s important to realize that the suitability and safety of PVC largely depends on the specific type of PVC used and the environmental conditions it encounters.
Here are some key considerations:
Types of PVC: It’s important to distinguish between the different types of PVC. Unplasticized PVC (uPVC) and Chlorinated PVC (CPVC) are generally considered safer options compared to regular PVC. uPVC, lacking plasticizers, is less likely to leach chemicals, and CPVC can withstand higher temperatures, reducing the risk of leaching under heat. If uPVC or CPVC are not readily available, regular PVC can be used, but it’s prudent to verify its NSF standards for safety.
- Unplasticized PVC (uPVC), which doesn’t contain plasticizers, is often considered safer for water transport as it’s less likely to leach chemicals.
- Regular PVC (written as just PVC), contains plasticizers like phthalates to make it more pliable. These plasticizers may be able to leach out, especially under high temperatures, raising concerns about their use in systems where water circulates continuously.
- Chlorinated PVC (CPVC) is altered by a free radical chlorination reaction, increasing its chlorine content. CPVC is more flexible and can withstand higher temperatures than standard PVC.
Understanding NSF Ratings: Many PVC products, like Schedule 40 PVC (regular PVC) commonly found at hardware stores, come with NSF-14 and NSF-61 certifications. The NSF-61 certification means the product is approved for transporting potable (drinking) water. This implies that the material is safe for carrying drinking water under typical environmental conditions, not necessarily restricted to use outside buildings. The key is to ensure that the PVC isn’t exposed to conditions, such as extreme heat, which could promote leaching.
Environmental conditions affect the material depending on where you place your PVC and the subsequent temperature exposure from that placement.
- Temperature and light exposure can accelerate the breakdown of PVC and the potential leaching of harmful chemicals. For instance, PVC exposed to high temperatures or direct sunlight may release more phthalates or other additives.
- The pH level of the water can also impact the stability of PVC. Highly acidic or alkaline conditions may cause more rapid degradation of the material, increasing the risk of leaching.
Primer and glue are important variables as they are what binds your PVC together. In some cases, very rarely, you won’t have to use them, but if you’re growing indoors, a well-connected pipe is essential to prevent leaks.
- The safety of PVC in hydroponic and aquaponic systems is not just about the pipe itself but also the adhesives used to bond them. Some primers and glues can contain harmful solvents that may leach into the water.
- It’s important to choose adhesives that are certified safe for potable water systems and ideally those that are specifically recommended for use in food-grade applications.
In conclusion, while PVC can be used in hydroponics and aquaponics, it’s essential to select the right type of PVC and consider the environmental factors and adhesives used. Monitoring the system for any signs of degradation and opting for alternatives where feasible can further ensure the safety and effectiveness of your setup.
Can Plants Absorb Microplastics?
Another important consideration in hydroponics and aquaponics is the fact that you’re not actually drinking the water used in your systems, you’re just eating the plants that consume the water. And because the term “food grade safe” wasn’t necessarily coined with “hydroponics” in mind, it’s hard to officially designate what’s safe and what isn’t without a scientific “hydroponics/safe plastics scale.”
Regardless of this point, however, the question still remains: Is it possible for microplastics to be absorbed by the plant and then transferred to humans when they eat the plant? Well, the answer, it seems, is still being studied.
In some reports, such as one by the Pacific Northwest National Laboratory, microplastics and nanoplastics were not absorbed by plant cells, but did attach to the root cap, while in other reports, such as this one, microplastics did enter through the roots and into the leaves, the part that humans eat.
So what’s this all mean? Well, it means that hydroponic plants probably have an extra level of protection against absorbing microplastics and nanoplastics when compared to just consuming the plastic-touching water by itself — such as drinking out of a water bottle — but more and more studies are showing that it’s possible leaching does occur to some degree.
Questions and Answers (Q&A)
Here we address some of the most pressing questions about plastics, their impact on health and the environment, and the role of organizations like NSF in ensuring safety.
Where does this information come from?
The two primary sources of information used in this article come from Utah State University Extension and New York University. However, there were multiple sources used to highlight what’s outlined above.
Are there any general rules of thumb to follow?
Yes, when it comes to food safe products, there are couple rules of thumb that should probably be followed:
- If the product was obviously designed to store beverages, potable water, or food — such as a peanut butter jar — then it is indeed food safe if it has the correct triangle identifications above.
- If the plastic container held a chemical product — such as laundry detergent — then don’t use it, even if you’ve successfully cleaned it out.
Who is NSF and What is Their Role in Plastic Safety?
NSF International is an independent organization that develops standards and conducts product testing to ensure public health and safety. In the context of plastics, NSF certifies products like plastic piping and containers to ensure they meet strict health and safety standards, especially when used in food-related applications or for carrying drinking water.
What are Microplastics and Nanoplastics?
Microplastics are tiny plastic particles less than 5mm in size, often resulting from the breakdown of larger plastic items. Nanoplastics are even smaller, typically less than 100 nanometers, and can arise from similar sources or be manufactured. Both can be environmental pollutants and are a concern due to their potential to infiltrate ecosystems and the food chain.
How Do Microplastics Enter the Environment?
Microplastics can come from a variety of sources, including the breakdown of larger plastic waste, cosmetic products with microbeads, synthetic fibers from clothing, and the deterioration of car tires.
Can Microplastics Affect Human Health?
The impact of microplastics on human health is an area of ongoing research. While they have been found in human tissues, the extent and nature of their health effects are still being studied.
Are All Plastics Recyclable?
Not all plastics are recyclable. The recyclability depends on the type of plastic, its condition, and local recycling facilities. Commonly recyclable plastics include PET, HDPE, and LDPE.
What is BPA, and Why is it a Concern?
BPA (Bisphenol A) is a chemical used in making certain plastics and resins. It’s a concern because it can leach out of plastic containers into food and drinks, potentially affecting human health due to its estrogen-mimicking properties.
How Can I Reduce My Exposure to Plastic?
Reduce plastic use by opting for reusable items, avoiding single-use plastics, choosing glass or metal containers, and being cautious with plastic containers, especially when heating food.
Can Plastic Ever Fully Biodegrade?
Most conventional plastics do not biodegrade. They break down into smaller pieces over time, but the polymers can persist in the environment for hundreds of years.
What are Bioplastics, and Are They Better for the Environment?
Bioplastics are made from biological materials like cornstarch and sugarcane. They are often more environmentally friendly, as some types are biodegradable, but their impact varies depending on how they are produced and disposed of.
How Do Microplastics Affect Hydroponic and Aquaponic Systems?
Microplastics can enter these systems through contaminated water or degraded plastic components. Their impact on plant health and growth is a subject of ongoing research, with potential concerns about absorption and accumulation in plants.
Can Microplastics Be Absorbed by Plants?
Some studies have suggested that microplastics can attach to plant roots and, in some cases, be absorbed and transported to other plant parts. However, research on this is still evolving.
What is ‘Food Grade Safe’ Plastic and Why is it Important in Hydroponics and Aquaponics?
Food grade safe plastics are those deemed safe for contact with food and beverages, as they don’t release harmful chemicals. In hydroponics and aquaponics, using these plastics ensures that the water and plants remain uncontaminated by plastic additives.
How Can I Ensure the Plastics I Use in My Hydroponic/Aquaponic System Are Safe?
Choose plastics with appropriate safety certifications (like NSF-61), opt for food-grade plastics, and avoid materials known to leach harmful substances.
Are Certain Types of Plastics Safer Than Others for Hydroponic and Aquaponic Systems?
Yes, plastics like uPVC, HDPE, and LDPE are generally safer as they are less likely to leach harmful chemicals compared to others like PVC with plasticizers.
What Are the Risks Associated with Using Non-Food Grade Plastics?
Non-food grade plastics may leach harmful substances into the water, which can be absorbed by plants, potentially affecting plant health and consumer safety.
How Do Environmental Conditions Affect Plastic Safety in Hydroponics and Aquaponics?
Factors like temperature, sunlight exposure, and water pH can affect the rate at which plastics degrade and leach chemicals, potentially increasing contamination risks.
Can Recycled Plastics Be Used Safely in Hydroponic and Aquaponic Systems?
While using recycled plastics can be environmentally friendly, it’s important to ensure they are free from contaminants and safe for use in food production systems.
How Can I Reduce the Risk of Microplastic Contamination in My System?
Use high-quality, durable plastics, avoid unnecessary degradation of plastic components, and regularly inspect and maintain your system to prevent plastic breakdown.