A complete guide on using plastic for food storage including how to use plastic in the safest way possible.
The Safest Plastics for Food Storage Include:
- #1 – PET or PET (Polyethylene Terephthalate)
- #2 – HDPE (High-Density Polyethylene)
- #4 – LDPE (Low-Density Polyethylene)
- #5 – PP (Polypropylene)
Plastics That Should Not be Used for Food Storage:
- #3 – PVC (Polyvinyl chloride)
- #6 – PS (Polystyrene)
- #7 – “Other” Can contain BPA (Bisphenol A)
Not all plastics are created equally, especially when it comes to food storage. Some plastics easily leach harmful chemicals into food, while others are much safer. Do you know the difference? Below I’ll lay out the details on which types of plastic can be used for food storage including rules that should be followed no matter what type of plastic you have.
What Does “FDA Approved” Mean?
For a plastic to be considered FDA Approved “Food Safe,” it means the plastic must meet certain criteria laid out by the FDA for safety. In particular, the item must be able to withstand certain environmental strains.
For example, if a yogurt cup gets a plastic lid heat-sealed onto it, the plastic has to show that it won’t leach chemicals into the yogurt after the application of heat.
Plastic must also show that it won’t leach chemicals into the food within the shelf-life of the food, or that it won’t leach a dangerous level of chemicals into the food.
What is the Resin Identification Code?
The resin identification code is the little number inside the triangle stamped on the bottom of plastics.
In 1988 The Society of the Plastics Industry (SPI) created the resin identification code to help plastics manufacturers and recycling facilities identify what type of plastic resin was used on that product.
There are currently 7 resin identification codes. Numbers 1-6 identify a specific type of plastic and number 7 is a catch-all category for any of the other hundreds of types of plastics.
FDA Approved Food-Grade Plastics
Plastic #1: PET or PETE (Polyethylene Terephthalate)
PET or PETE is commonly used to make:
- Soft drink, juice, and water bottles
- Condiment jars (salad dressing, pickles, and peanut butter)
PET (or PETE) is polyethylene terephthalate or plastic number 1. PET is labeled plastic number 1 for a good reason: it is one of the most common materials in plastic manufacturing worldwide. When it is used to make fabric we refer to it simply as polyester.
PET is known to be strong, clear, and lightweight is used not only in every single-serve and 2-liter drink container in the United States but over half of the world’s synthetic fiber production.
PET creates an impermeable barrier between food and the environment and is good at keeping gasses and moisture out.
While PET is considered safe for single-use, you shouldn’t reuse number 1 plastic containers or expose them to heat.
Plastic number 1 can be recycled and is one of the few plastics that are food safe in their recycled state.
Plastic #2: HDPE (High-Density Polyethylene)
HDPE is commonly used to make:
- Milk jugs
- Some juice and water containers
- Food storage buckets
- Some toys
High-density polyethylene or HDPE is plastic number 2. It can be clear or colored and makes a somewhat rigid plastic that is used specifically for food items that have shorter shelf lives, like milk.
Only virgin, non-recycled HDPE is considered food safe. Not only this but milk jugs can be hard to properly sanitize, which is an additional factor that makes them unsuitable for re-use.
Food storage buckets are commonly made of HDPE, and these are safe to store food in but don’t use plastic trash bags made of HDPE to line other food storage receptacles.
Plastic #4: LDPE (Low-Density Polyethylene)
LDPE is commonly used to make:
- Bread bags
- Frozen food packaging
- Squeeze bottles for condiments
Low-density polyethylene (LDPE) is less rigid than HDPE and is considered to be a bit safer than other plastics. LDPE is more resistant to breakdown at higher temperatures and is less prone to leaching toxins. That said, number 4 plastic is not considered food safe if it has been recycled.
Many Tupperware-style containers are made of number 4 and 5 plastics.
Plastic #5: PP (Polypropylene)
PP is commonly used to make:
- Yogurt cups
- Single-serve containers
Polypropylene is one of the least reactive plastics, along with plastic number 4. It holds up well in a range of temperatures and doesn’t easily react with any type of food.
Polypropylene is both durable and flexible and is considered microwave-safe (although see my warnings below–you shouldn’t microwave any plastic).
Plastics Unsafe for Food Storage
Plastic #3: PVC (Polyvinyl chloride)
Polyvinyl chloride is commonly used to make:
- Plastic plates
- Cling wrap
- Baby toys
- Industrial uses (pipe, siding, tiles, electrical cables)
PVC is a very durable and hard-sided plastic but it is not safe for food storage, cooking, or even warming your food in.
PVC contains phthalates, ethylene dichloride, lead, and cadmium just to name a few. See below for more information on the dangers of these chemicals.
Plastic #6: PS (Polystyrene)
Polystyrene is commonly used to make:
- Egg cartons
- Meat trays
- Styrofoam to-go containers
Polystyrene is the main chemical used to make styrofoam and it is not safe for food storage long-term or repeated food storage. Styrene is considered to be potentially cancer-causing by several large environmental health organizations, especially when heated.
Plastic #7: “Other” Can contain BPA
Plastic #7 are commonly used to make:
Plastic number 7 is a catch-all category for any of the other types of plastic resins besides the first 6 listed above. There are hundreds of types of plastic resins and anything labeled with a #7 could contain one or a mixture of several plastics.
Since no one can say for sure what type of plastic was used, don’t assume it’s safe. Don’t use it to store food long-term, and certainly don’t heat or freeze your food in it.
Dangerous Chemicals in Plastics
The most famous of the Bisphenol family of chemicals is Bisphenol A, known as BPA. BPA was banned from baby bottles and children’s food packaging in 2012 after a link was found between BPA and infant brain and reproductive defects.
You’ll see many products marketed for adults labeled “BPA-free,” but be aware that BPS and BPF, which are used as replacements for BPA, may do similar cellular harm to both children and adults.
Phthalates are used to add flexibility and durability to rigid plastics and can be found in plastic wraps and flexible food packaging. They are sometimes called plasticizers and are found in hundreds of products from plastics to soaps and shampoos.
Phthalates are known to damage reproductive systems in animals and the CDC has measured phthalates in a large proportion of the US population.
You can be exposed to phthalates by eating and drinking from containers that contain phthalates.
Lead, mercury, chromium, cadmium, and antimony are among the most dangerous heavy metals to human health. They can induce neurological or kidney damage if you’re exposed to enough. Plastics can have heavy metals in them if they were exposed to them in the recycling process or during certain manufacturing processes of virgin plastic.
Most commonly plastics that are very old or highly abraded and damaged are likely to begin leaching heavy metals.
Per- and Polyfluoroalkyl Substances (PFAS)
PFAS belongs to a group of chemicals that include more than 5,000 substances that are used to make non-stick pans, fast food wrappers, takeout containers, and microwave popcorn bags, just to name a few.
These chemicals linger in the human body and have been linked to various cancers as well as endocrine disruption.
Other Chemicals in Plastics
There are thousands of chemicals used in the manufacture of plastics worldwide.
Factors that Affect Plastic Safety
In addition to the chemical substances that plastics are made of there are other factors that affect how fast a plastic will break down. At the end of the day, no plastic is perfectly stable, and all are subject to breakdown at various rates.
Heat helps degrade the chemical bonds in plastic, and when plastic is heated chemicals will begin to leach out of the container and into the adjacent food.
Studies have even shown that single-use water bottles begin to leach chemicals after sitting in the sun for a few hours.
The tiny abrasions from using utensils against plastic storage containers and the scratches from washing plastic make it easier for the plastic to break down and leach chemicals.
This is why to-go containers and certain numbers of plastic should never be re-used, even if they seem to be in perfectly good shape to you.
Additionally, these small scratches can release tiny particles of the plastic itself, which are very harmful to human health.
Type of Food Stored Inside
Highly acid foods can react with the chemicals in your plastic container and leach some of them out. Fatty or oily foods can also leach out plastic chemicals because some plastic chemicals are actually fat-soluble!
Strong detergents are designed to well, break apart food molecules. The problem is that some strong detergents can also begin to break down plastics. If you are reusing plastic containers, use mild detergents.
How To Use Plastic Containers to Store Food
For Re-Used Plastic Containers
Find the Plastic Code
The resin identification code will easily tell you which type of plastic you’re dealing with.
Remember, only use numbers 1, 2, 4, and 5 to store food. Number 1 plastic (PET or PETE) is the most abundant reusable container you can find (2-liter soda bottles, Gatorade bottles, etc) and provide a sufficient barrier against gas and moisture exchange for a few years.
Only Use Containers with Screw-On Lids
Pop-top lids (like the kinds on milk jugs) won’t sufficiently keep out air and moisture like screw-on lids will.
Even then, some screw-on lids won’t provide a perfect seal once they’ve been opened. To test the bottle and see if it will work, screw on the lid and hold it underwater to see if any air escapes. If you do, don’t use this container.
Wide-mouth jars like peanut butter jars don’t tend to form good seals, so even though I like the wide-mouth design, I don’t usually use them for food storage.
Don’t Use Thin Plastic Bottles
Thin plastic, like the kind you get with bottled water, really doesn’t cut it for long-term food storage. The thinner plastic is even more permeable to air and rodents.
Only Use Bottles That Previously Held Food
Don’t use bottles that held anything non-edible in the past. It’s too hard to make sure you properly cleaned the bottle and it’s just not worth the risk of contaminating your food. There are plenty of unused soda bottles in the world. Just recycle or throw away anything that held non-food items.
Don’t Use Harsh Detergents
Rotate Out Your Food
One of the most important factors in storing food long-term is removing the oxygen from the container. Exposure to oxygen causes food to age and spoil.
If you choose to re-use plastic bottles keep in mind that these plastics (particularly number 1 plastics) will not stop gas absorption forever. They will work for a few years with an oxygen absorber in them, but eventually, there will be some gas exchange through the plastic.
For this reason, you should rotate out any food stored in re-used plastic along with your other short-term storage items.
Rodent-Proof Your Food Storage
Re-used plastic bottles are not rodent-proof. If you using many smaller single-serve bottles, consider storing them in a larger Rubbermaid tub with a lid. Take steps to trap rodents in your storage space and keep an eye out for food they may have gotten into.
Use an Oxygen Absorber
Regardless of whether you’re using a new or re-used container, you need to place an oxygen absorber in your container. This not only helps keep the food fresh but kills any insects or insect larvae that may be hiding out in the food.
There is some controversy as to whether oxygen absorbers will kill insects inside plastic bottles but this study showed that PETE bottles performed well when storing low moisture foods.
For New Plastic Containers
Use New Plastic
New plastic is safer to store food in than re-used plastic. New plastic doesn’t have any micro-abrasions and won’t have been washed in a hot dishwasher with harsh detergent.
Use Food Grade Plastic
Food grade five-gallon buckets can be used to store dry items. These items should be 10 percent moisture or less and have a low oil content. Only choose buckets with gaskets that seal the lid and never use buckets that held nonfood in the past.
Keep All Containers Cool and Out of Direct Sunlight
Even if you’re using food-safe plastic, be sure to keep it in a cool, dark room out of direct sunlight. The repeated heat from sunlight will degrade plastic and make it unsafe over time. This applies to both new and re-used plastic containers.
Store Acidic and Oily Foods in Non-Plastic
When you’re readying a pantry for long-term emergency use you will invariably need to store acidic and oily foods. The best method for storing items like this is to use glass, metal, or ceramic as they will keep the food the freshest the longest. The applies to both new and re-used plastic containers.
Safer Alternatives to Plastic Food Storage
Glass is unequivocally safer for food storage than plastic. Glass is made of abrasion-resistant silicone which does not get scratched easily and cannot leach dangerous chemicals because it doesn’t have any.
You can store glass in direct sunlight with no effect on the glass (although the food inside might be altered).
Unlike plastic, glass won’t retain smells of food previously stored in it.
Of course, the main downside to glass is that it is heavy and may not be as compact as plastic containers.
Metal is also a very safe food-storage option but the type of metal needs to be taken into account. Food-grade stainless steel, which is sometimes labeled as type 304, 18/8, or 18/10 is the most common type of metal used in food storage today.
This type of steel won’t oxidize (react) against acidic foods like tomatoes.
Stainless steel does not absorb the smell of the food stored and is more lightweight than glass.
To use metal effectively you do need to invest in a machine that can seal the metal lid to the can.