Plastic has had a bad “wrap” of late, with many consumers now basing at least some of their purchasing decisions on packaging sustainability as well as the price and quality of products. Questions such as whether packaging is compostable, or recyclable now regularly feature in consumers’ priorities when choosing a brand.
However, it’s worth remembering that plastic plays a vital role in protecting products. Techniques such as vacuum sealing can help to reduce food waste, which is a significant contributor to CO2 emissions. In fact food waste is estimated to release around 8-10% of the world’s greenhouse gases.
What Are the Types of Vacuum Seal Bags?
Vacuum sealing is commonly used to store food for longer periods of time, prevent bacteria from compromising the quality of the food, and preserving the taste and texture. While vacuum seal bags are typically made from plastic, not all plastic bags are made equal.
Vacuum seal bags are known as barrier bags and are made from materials that significantly reduce the oxygen transmittal rate (OTR). That’s a measurement of how porous the material is, and therefore, how much air can still seep out of the bag, even after it’s sealed.
As an example, many standard freezer bags are made from low-density polyethylene. This material has an OTR of around 7,000-8,500 cc/m2/24 hours. Compare this to a good quality vacuum seal bag which has an OTR of around 0.08-0.19 cc/m2/24 hours.
What Are They Typically Made of?
Vacuum seal bags can be made from a wide range of plastics. Some of the most common plastics include: Polyethene (PE), Polyvinylidene chloride (PVDC), Polypropylene (PP), Polyvinyl Chloride (PVC), Polyester (PET), and Polyamide (PA).
Bags used in vacuum sealing are often made from polypropylene (PP) or polyamide (PA) multi-layer plastic film, known as co-extruded films. These types of bags are clear and commonly used to package food items such as meats and cheeses. Most 3mm co-extruded bags have an OTR of 5 or less.
For even greater barrier protection, some vacuum seal bags have an extra coating of ethylene vinyl alcohol (EVOH), which further reduces the OTR. Typically, 3mm bags made from these materials may have an OTR of 0.02!
In some sectors, such as the coffee industry, foil bags coated with polyester (PET) are used. Foil offers an even lower OTR than plastic, and foil barrier bags can have an OTR or 0.0006! Additionally, foil vacuum bags can block out light, which is another important aspect for preserving flavours.
What Determines Their Quality?
High quality vacuum seal bags are essential to ensure your food is well-preserved. There are three key factors which will impact the success of your vacuum sealed packaging.
The Materials the Bags are Made From
As we already mentioned, not all plastics prevent air from seeping out of the bags. Standard freezer bags, made from polyethylene, can lose the vacuum seal within seconds, which is not great for preserving your food for the long-haul!
You should also consider what you plan to use the bags for. Vacuum seal bags used in food storage need to be made from food-grade materials. They also need to be resistant to high or low temperatures, so that you can freeze or sous-vide the contents.
The Bags’ Thickness
The success of your vacuum sealing is also dependent on the thickness of your vacuum seal bags. Freezers are notorious places for bumps and knocks, as we rummage around for exactly what we’re looking for (usually in a hurry!). Even a small tear in your bag can lead to deterioration in your food’s quality.
Choosing a thicker bag, as well as ensuring any sharp bits like bones have been covered, will prevent the bags from accidental rips.
The Bags’ Texture
If you look closely at a vacuum seal bag, you’ll notice that the back is thicker. The back of the bag is usually textured and it’s an important feature to look for when choosing your vacuum seal bags. The texture comes from hundreds of air valves that are invisible to the naked eye. These one-way air valves allow air out of the bag, but prevents it from getting back in.
Are Vacuum Seal Bags Recyclable?
Given that vacuum seal bags are made from plastic, it may be counterintuitive to think that vacuum sealers are eco-friendly. However, if you consider that vacuum sealers help us to store food for longer, keep more of it out of landfill and present it in an appealing way to consumers, then vacuum sealing is, indeed, an eco-friendly process.
Even if we simply ask the question, “Are vacuum seal bags recyclable?”, we’ll find that the simple answer is “yes”!
Despite being made of plastic, many vacuum seal bags are recyclable provided they’re clean and dry. While it may not be as simple as popping them in your home recycling, there are many collection points around the country which will accept bags for recycling.
Summary
On the surface, using vacuum sealing in the food industry may seem like a huge contributor to plastic waste and poor sustainability practices. However, when you consider that vacuum sealing helps us to get food to the consumer in good condition and keep it on the supermarket shelves for longer, it turns out that, vacuum sealing is a very eco-friendly process in the long run.