What are the benefits of flow wrapping sandwiches?

Jun 28 2023

The great thing about sandwiches is that it’s not just the contents that are personal: it’s also what you choose to call them too. Americans seem to have cornered the market in naming them and you can sometimes spot where they are from after hearing the name used.

A Wedge, for example, is purported to come from Yonkers in New York while a Poor Boy is from the lower Midwest. In the UK they vary depending on where you are from too and the type of bread. A roll, for example, can be a bun, bap, barmcake. muffin or, in Warwickshire, a batch.

Regardless of this, when it comes to any food packaging, particularly prepared sandwiches, there are usually three main priorities: keeping everything clean, keeping it chilled and ensuring that it can be packed quickly making the product look fresh and appetizing. All are important considerations but for different reasons.

What are the flow wrapping advantages?

While there are many ways to package sandwiches, flow wrapping or flow packing as it is also known, is a cost effective and efficient way of achieving this. Flow wrapping is also called horizontal bagging, pillow-pouch wrapping, fin-seal wrapping and crimp-seal wrapping.

In its usual sense, flow wrapping is where the product moves horizontally along a machine, then wrapped in laminated film or paper that is completely sealed by horizontal flow wrapping machines.

It is invariably a horizontal flow wrapping machine in use as vertical flow wrapping is usually better for dry goods or ones that fall easily, including bagged salads or loose-leaf lettuce.

What type of product is flow wrapping suitable for?

Any solid item that can be pushed along a horizontal belt or surface, is suitable for flow wrapping. Chocolate bars, packs of face masks, greetings cards, cut herbs, vegetables; any product that needs to be put into a bag, that can ultimately be pushed or conveyed.

Small granular items do not work for horizontal flow wrapping, vertical form fill seal is best for this kind of product.

How will the flow pack appear?

Normally a rectangular pack is created by flow wrapping although square bags can also be generated just as easily too. Whichever option is selected, the bag can be printed clear or in multiple colours. With the addition of inline printing and labelling, efficiencies can be achieved in time and labour.

What benefits does flow wrapping offer?

Flow wrapping can preserve raw materials and offer better protection than some other options. Material technology has resulted in a greater choice with compostable, biodegradable, recycled and recyclable packaging favoured. This can still fulfil all the requirements necessary for sandwich packing but ensuring the environment is cared for too due to its sustainable credentials.

Additionally, well-constructed flow wrapping reduces the packaging around the product so that it remains tight, reducing movement and damage in transport and display. Additionally, the pack can be neatly placed in outer packaging, reducing the number of resources needed and aiding transport.

How is preservation in sandwiches flow wrapping achieved?

While aesthetics continue to be essential in shelf appeal with a flow pack that has a neat finish and tight gusseted ends, food sanitisation and hygiene are essential elements too.

Modified Atmosphere Packaging (MAP) or gas flushing is the practice of modifying the atmosphere inside packaging containing perishable foods including sandwiches.

The aim of the process is to improve the shelf life and freshness of the sandwiches. It is quite harmless as the oxygen is removed as part of the packing process and replaced by, most commonly, nitrogen or carbon dioxide. It is also used on fish, meat, and cheese too, again to safely improve shelf life.

Oxygen produces lipid oxidation reactions and causes high respiration rates and are to blame for shortened shelf life. The oxygen encourages the growth of aerobic spoilage, and the formation of other unwanted microorganisms may also potentially occur.

The MAP or gas flushing process lowers the volume of oxygen contained within the empty space of the packaging containing the product, preventing the formation of water vapor.

What materials are used?

Just like vertical form fill seal, the packaging materials for a flow wrapper packing sandwiches are made of either:

  • Biaxially oriented polypropylene (BOPP) - is a thermoplastic polymer that has many similar properties to PET (Polyethylene Terephthalate). It is commonly used in food packaging, bottle caps, and other applications.
  • Polyethylene terephthalate (PET) - a common thermoplastic polymer resin of the polyester family, often used for containers of liquids and food.

Both are common and popular, they are strong, robust materials that keep products fresh. These materials are recycled and recyclable making their green credentials stronger.

What are the Efficiency Opportunities?

The pack rate for sandwiches accommodates from 10 to 120 packs per minute depending on the feed input rate, size of the product and material used. Additionally, flow wrapping allows printing and labelling to be fulfilled online, within the flow wrapper web. This allows the packing process to be completed in one pass to increase labour efficiency and reducing unit costs.  Online printing and/or labelling also reduces line lengths and maintenance costs.