Today's consumers have the expectation that vacuum packaged food products will be fresh and wholesome when opened. To meet this expectation, packagers must consider a few critical requirements including the storage bag configuration, the correct bagging material, and the appropriate packaging process. When done properly, vacuum packaging can extend freshness, preserve texture and appearance, protect nutritional value, and maintain the flavor of food significantly longer than many other food storage methods. The demand for quality is the same whether the commissary focuses on small retailers or serves large scale, chain store operations.
Many food products have unique vacuum packaging requirements. Coffee, for example, requires a different set of criteria, (bag material, packaging process, etc.) than cheese, or fresh chicken. When considering vacuum packaging a product, it is important keep a few things in mind:
• How long will the product remain in the package?
• Is the product wet or dry?
• Is microbial contamination or oxidation an issue?
• Will the product require modified atmosphere packaging?
Understanding how the contents of the bag can and will affect the packaging, is key in determining the specific packaging process required, the bag style, bag material and the most appropriate choice in packaging equipment.
Choosing the Appropriate Process
Vacuum packaging equipment can be found in a wide variety of configurations, but usually follows two common approaches: nozzle-style vacuum machines and chamber vacuums.
The most versatile method of vacuum packaging is by means of a nozzle-style machine. Designed for horizontal or vertical use, nozzle-style vacuum sealers range in sealing lengths from 12” to over 120”, and are available in both tabletop and floor standing versions. This style of machine is ideal for vacuum-sealing solid or bulky food products. Nozzle-style vacuum packaging is relatively uncomplicated. A filled bag or pouch is placed between a set of sealing jaws, over stainless steel vacuum nozzles that extend between the jaws. The jaws grip the bag while air is evacuated through the nozzles by means of a vacuum pump or venturi system. Next, if desired, gas is flushed through the same set of nozzles into the bag. At the end of the vacuum or gas cycle the remaining air or gas is evacuated, the nozzles retract from the bag, and the sealing cycle is completed. Most machines enable the operator to vacuum seal one or two bags per cycle - depending upon the model and bag specifications. One of the advantages of nozzle-style machines is that they often require a shorter cycle time. Specialized sealers with multiple nozzles enable 4 or more bags to be sealed in a single cycle.
Vacuum chambers offer a high level of vacuum and consistency. This easy-to-use method of vacuum sealing bags is chosen when the highest degree of vacuum is required (for example, when packaging meat or cheese). Vacuum chambers vary from small tabletop units to large, floor standing, single and double chambers. Like nozzle-style vacuum packaging, vacuum chamber packaging is a fairly straightforward process. A filled bag or pouch is placed on the bed of chamber with the open end positioned in contact with the seal bar. The hood of the chamber is closed after the product has been loaded, and the vacuum cycle begins automatically. A vacuum pump removes air from the entire chamber. This step may be followed by a gas flush cycle(s), if required. The sealing cycle begins immediately after the vacuum or gas cycle has completed. The hood of the chamber opens automatically at the end of the sealing cycle. With bags lined up along the length of the sealing bar, vacuum chamber machines can package as many bags per cycle as the sealing bar length will accommodate. Vacuum chamber sealers are excellent for powdery foods as well those packaged in liquid. Unlike the nozzle-style vacuum, the entire chamber is evacuated, eliminating the possibility of pulling powdery or liquid material into the vacuum nozzles.
Vacuum packaging in one form or another has been at the center of food preservation for generations. Although once exclusive to commercial food packagers and processors, vacuum packaging is now available to small-scale food processors as well as home users. Modern equipment now ranges in size from home “food saver” models to high production, high volume industrial systems. Vacuum packaging has, and will continue to be a key process for preserving flavor, color and texture - and for ensuring a wholesome and available food supply.