You have probably asked the question: Do Mylar bags leach chemicals? Properly manufactured, food grade Mylar bags do not leach harmful chemicals under normal storage conditions.
Let's break it down.
What Are Mylar Bags?
The term Mylar was developed by DuPont to refer to the brand name of a product originally manufactured by them and is now generally used in the context of packaging as a commonly used type of laminated polyester film.
The majority of mylar bags manufactured for use with foods/consumer goods consist of at least two bonded materials:
1. Polyester film (usually referred to as mylar)
2. Aluminum foil for protecting against moisture and oxygen
3. A food contact layer (most likely a lower density polyethylene material)
Each layer has its own purpose. The two outer layers are there for protective strength and oxygen exclusion while the inner layer is designed to be safe for direct contact with food.
Do Mylar Bags Leach Chemicals Into Food?
Under normal conditions, food grade Mylar bags are considered chemically stable.
The material of the inner food contact layer has been manufactured with materials that have been evaluated by the FDA as not being migratory into food while at room temperature or in extended storage conditions.
As a result, Mylar bags are commonly used for:
- Long term storage of dry goods
- Packaging of coffee and/ or tea
- Packaging of any kind of supplement and/or powder
- Long-term emergency food storage
Chemical leaching could potentially occur only if bag conditions exceed what was intended by the manufacturer.
This depends entirely on whether the bag meets food safety standards, which is explored further in our blog "Are Mylar Bags Food Safe?"
When Chemical Leaching Could Happen
There are an increased risk from using Mylar bags incorrectly in the following situations:
- High-temperature cooking (above boiling)
- Direct exposure to flame
- Using low-quality Mylar bags or those that aren’t food safe
- Long-term storage of food with high acidity or fat content at elevated temperatures.
The greatest risk to Mylar bags comes from heat. The polyethylene inside the bag will melt or break down combustible (under a high enough temperature) and is therefore not intended to be used for cooking unless otherwise noted by the manufacturer.
Are Mylar Bags BPA Free?
The majority of today’s Mylar bags are free from BPA (Bisphenol-A) from the manufacturers to the consumer level (i.e., food packaging, supplement packaging). Bisphenol-A is primarily related to composite rigid plastics rather than laminated polyester films.
However, not all Mylar Bags will meet the same construction requirements. Established companies will usually have this clearly indicated on their product labels or wording, i.e., non-toxic and compliant to FDA regulation.
Mylar vs Plastic Bags for Chemical Safety
Similarly to standard plastic bags, Mylar also provides multiple safety benefits:
• Improves barrier against oxygen/moisture
• Higher chemical stability over time
• Lower permeability to outside contaminants
• Reduced chance of odors/flavors migrating between items in packaging.
As a result, Mylar is typically preferred for products that may require long term storage without degradation over time.
How to Make Sure Your Mylar Bags Are Safe
Follow these guidelines if chemical safety is an important factor in your product or if you will be needing to store your items with chemical safety in mind:
1) Use Mylar bags that are food grade.
2) Do not expose Mylar bags to extreme heat.
3) Store your Mylar bags in a cool, dry location.
4) Do not use (or reuse) Mylar bags that are damaged or warped.
When properly sourced, Mylar bags are one of the safest presently available types of flexible packaging.
What About Customized Mylar Bags?
As far as safety is concerned, customized Mylar bags share the same safety fundamentals as stock bags; however, there are a couple of safety considerations that can be advantageous for custom bag users if done correctly.
Customized bags are generally created using food grade base films, which are printed, laminated after the fact. The printing inks are located on exterior layers of the bag, meaning the product is not directly exposed to ink while in the bag but rather separated from it by barrier films and sealant films. As a result, the product only comes into contact with the inner food safe layer, preventing it from coming into contact with the printing inks, coatings, and other filament.
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