It is almost impossible that you haven’t seen or opened a vacuum-sealed product at least once in your life. For most of us, it’s a daily task.
Simply walking down the cold section at your local supermarket reveals a wide variety of vacuum-sealed products, from fish to meat to cheese, and many others. Vacuum sealing is everywhere, but have you wondered how it works and why we vacuum seal some types of food but not others?
Well, you’re in the right place. The science behind vacuum sealing is a fascinating dive into food preservation, making it one of the most effective ways that we can all help reduce food waste and keep our food fresh for longer.
What is Vacuum Sealing?
Vacuum sealing is a simple and straightforward process, though it does require some specialised technology. The food product, say a piece of steak or a fillet of salmon, is placed inside a plastic sleeve. The edge of the sleeve is then placed into a vacuum sealer. The air is then sucked out completely and the packaging is sealed airtight to create an impenetrable barrier and food-safe environment.
But what is it about the absence of air that keeps the food fresh and safe to travel long distances to the shelves of our local shops?
You might be thinking that it is the air that is carrying pathogens like bacteria and fungi, but the bacteria are usually already in there, locked inside the sealed plastic. It’s just a tiny food-safe amount. These bacterial strains, in small amounts, are generally completely harmless. Our immune systems can easily handle these low traces of bacteria, but if they grow and multiply, they can cause problems such as food poisoning and other infections.
So, what’s the science behind keeping bacteria at low, safe levels?
The Science of Food Spoilage
Aerobic bacteria and fungi need air, specifically oxygen, to multiply. Without it, they can’t reproduce, and they remain at the low levels they were at when they were sealed away. By Australian law, food manufacturers must keep the amounts of certain bacteria under a specific threshold to ensure they remain safe for consumption. Our bodies and immune systems are remarkable things, and even the more dangerous strains of bacteria, like the dreaded E. coli, can be tolerated in very small trace amounts without any ill effects.
However, once the packet is opened, oxygen floods back in, and bacterial and fungal activity ramps back up. This is why a packet of meat can sit on a shelf safely for a week but needs to be cooked and eaten within a couple of days after opening.
It’s not just bacteria we have to worry about. Certain foods, especially animal products, do not do well when subjected to air for too long. Even if pathogens weren’t an issue, air exposure reduces the quality of meat and fish, drying it out and causing it to become stringy, chewy, and incredibly unpleasant to eat.
The Effects of Moisture and Bacteria on Food
While maintaining the moisture quality of the food is incredibly important, too much moisture can also cause the food to spoil and decay. This is because anaerobic bacteria, which do not require oxygen, thrive in a moisture-rich environment. Vacuum sealers help ensure this delicate balance in keeping the moisture levels just right to maintain food quality without compromising food safety, especially when it comes to meats and seafood.
With both oxygen and moisture kept under controlled levels, the food items enjoy a high level of protection against oxidation and microorganisms. In high-oxygen or moisture-rich environments, bacteria thrive but starved of their fuel, they go dormant until they are reawakened again once the packet is opened.
How Vacuum Sealing Preserves Freshness
We know now what vacuum sealing is and how it works, but what else can it do? What other benefits does it bring to the contents of your refrigerator or pantry?
The vacuum sealing technique retains the food’s inherent moisture and nutrients, almost freezing it at the quality it was at the time it was packaged. Speaking of freezing, vacuum-sealed food is protected from freezer burn as the lack of abundant moisture inside the packaging prevents ice crystals from forming. This is particularly important in maintaining the quality of chicken or seafood but is also effective in storing vegetables over the long term.
There are very few foods that do not benefit from being stored in a vacuum seal. Meat, fish, seafood, fruits, vegetables, legumes, and nuts all benefit from being sealed fresh, and a range of bag and container sizes are available to handle any food item.
Vacuum sealing can also help you to eat healthily by extending the shelf life of perishables after opening, allowing you to buy and prepare ingredients in bulk, and even allowing you to meal prep and keep individual portions of a meal fresh and safe to eat. By adding vacuum sealing to your daily routine, you can save money and reduce the number of times you have to visit the store.
Additional Benefits of Vacuum Sealing
Other benefits of vacuum sealing your food include:
- Longer shelf-life: By preventing bacterial spoilage, sealed food has a greater longevity than traditionally stored food.
- Space-saving: Vacuum sealing takes the exact shape of the food, meaning no more bulky containers.
- Food safety: The sealed bag prevents air, moisture, bacteria and other pathogens, creating the perfect environment to store food.
- Fresher taste: What goes in is what comes out again, with sealed foods retaining their original flavour and texture.
- Food waste reduction: Vacuum sealing contributes to sustainability by sharply reducing food waste.
Vacuum sealing isn’t just about food storage; there is also a French cooking technique that uses this storage method to create perfectly cooked meat, fish, poultry, and vegetables. Sous vide cooking (literally “under vacuum”) is a “low and slow” approach that poaches sealed food in a warm water bath, allowing food to cook perfectly evenly and retain its original moisture.
Common Misconceptions About Vacuum Sealing
As we see a lot of vacuum sealing in mass-produced supermarket products, some people might think that “vacuum sealing is only for professionals”. That could not be further from the truth. Vacuum sealers are now commercially available to anyone with the cheapest models no more than a couple of hundred dollars.
It is an easy and accessible method for anyone to use to get the most out of their food purchasing, providing efficiency and quality that can’t be replicated with other storage methods. It is important to remember, however, that while vacuum sealing slows spoilage, it doesn’t stop it completely. However, it can double the shelf-life of some of the most perishable food items we often buy.
For example, vacuum-sealed meat can last 1–2 weeks in the fridge, but non-vacuum-sealed meat will only last 3–5 days. In a freezer, the same timeframes for meat are 1–3 years for vacuumed and only 6–12 months for non-vacuumed.
Tips for Getting Started with Vacuum Sealing
Getting started on your vacuum sealing journey is incredibly easy; simply buy a vacuum sealing machine and its accompanying bags and away you go. Different models are designed for residential or commercial usage, so check your options and choose a model that fits the needs of yourself and your family or your business.
Once you’ve decided what you want to preserve, fill a single bag with your chosen food, and feed one end into the machine, which will draw out the air and then clamp down on the bag’s edge, sealing it from air and moisture.
Types of Vacuum Sealing Machines
There are two main types of vacuum sealing machines available on the market: chamber vacuum sealers and out-of-chamber sealers. Each type has its specific advantages.
Chamber Vacuum Sealers
Chamber vacuum sealers feature a chamber where both the product and the entire vacuum bag are placed. The machine removes air from the entire chamber, creating equal pressure both inside and outside the bag. This allows chamber sealers to:
- Handle liquids and moisture-rich foods
- Process multiple bags in quick succession
- Achieve a more consistent, quality seal
Chamber vacuum sealers are typically the preferred choice for commercial kitchens, food service businesses, and those processing large quantities of food at home.
Out-of-Chamber Vacuum Sealers
Out-of-chamber vacuum sealers only vacuum seal the open end of the bag which is placed across the sealing strip. The air is suctioned out through channels in the bag and an airtight barrier is created. They are a more compact and affordable option, making them popular for home use.
Types of Vacuum Bags
The type of vacuum sealer you choose will determine the kind of bags you’ll need to use. Choosing the right combination of machine and bags is crucial for achieving the best possible seal and maximising food preservation. The two main options are normal and channeled vacuum bags.
Normal Bags
- Used primarily with chamber vacuum sealers
- Smooth surface
- More affordable
- Clearer view of the bag’s contents
Channeled Bags
- Specifically designed for out-of-chamber vacuum sealers
- Unique texture and design to aid air extraction
- Heavy-duty and puncture resistant
Experience the Benefits of Vacuum Sealing with Pac Food
Sold on the idea of making your food safer, making it last longer, and preserving its flavour and nutrition?
Why not try one of Pac Food’s vacuum sealing machines to speed you on your way to eating better and reducing your food waste? Our domestic vacuum sealers range from models designed for small to moderate home use right up to frequent and even semi-commercial use!
Try vacuum sealing to enjoy fresher, longer-lasting food today to get the absolute best out of what you eat.