PART III PROCESS SAFETY
3. Packaging Systems
There are eight different types of packaging systems for gas packaging namely:
horizontal form-fill-seal machines for rigid and semi-rigid packages, horizontal and vertical form-sill-seal machines for flexible “pillow-pack” pouches, vacuum chambers machines, Gemella packaging system, Fibrelam system, Bag – in – car- ton systems, Bag-in-box system, Walki-Vent system and Flavaloc.
3.1. Horizontal form-fill-seal machines for rigid and semi-rigid packages (so-called deep-draw machines)
The system consists of 2 webs; the forming and non-forming web (figure 1).
The forming web is heated and the film is drawn into a forming die to create the desired pocket by the application of a vacuum or mechanical means. The foodstuff to be packed is then placed in the formed pocket, a vacuum is cre- ated, a gas mixture is injected into the package, and the package is sealed. The package usually consists of a semi-rigid base tray (PVC-PE) lidded with a thinner material. Suppliers are e.g. Multivac, Kramer&Grebe, Mahaffy&
Harder and Dixie Union. This type of packaging systems is mainly suitable for the retail packaging of meat, poultry, fish, cocked meats, bakery products, cheese and nuts.
3.2. Horizontal and vertical form-sill-seal machines for flexible “pillow-pack” pouches (so-called flow-pack machines)
The package is usually made from a single film and is totally flexible. These machines can also wrap a pre-filled tray of product, but are only capable of a con- tinuous gas flush. Although this allows a good level of purging of the air, mix- tures containing high levels of oxygen cannot be used due to the use of hot sealing jaws at the end of the machine. The air from the package is removed only by con- tinuous gas flushing. For certain very porous products (e.g. some bakery goods) substitution of the surrounding atmosphere is still insufficient to achieve the desired results. In such cases, an injection station can be fitted to the machine infeed so that the product itself is impregnated with gas immediately prior to packaging. Suppliers are e.g. Rose Forgrove, Aucoutourier, Fuji and Ilapak.
These kinds of packaging systems are mainly suitable for the retail packaging of bakery products, snack foods, coffee, cheese, nuts, meats, fish, salads and fruits.
3.3. Vacuum chambers machines
Preformed plastic bags and trays are used in these machines. Bags have been used for several years for prime meat cuts and cooked meats. Suppliers of machines using bags include Multivac. Trays are more recent development and are becom- ing more frequently usedl. Examples of such machines include the Dyno or Multivac “Space” machines, which can use pre-made HIPS, HDPE or PET trays.
FIGURE1. Different Food Packaging.
These types of packaging systems are suitable for both retail and catering pack- aging of meat, fish, nuts, and prepared meals.
3.4. Gemella packaging system
This system uses either form-sill-seal or preformed composite board-plastic trays.
Basically, Gemella packs can be sealed on any appropriate sealing machine with a gas flushing feature. The supplier is Mardon/Smiths in UK. The system can be applied to meat, poultry, fish, cooked meats, fruit, vegetables, cheese, bakery products, salads and ready meals.
3.5. Fibrelam system
The system involves the use of a preformed plastic laminated (polypropylene, polyester or ionomer/polyvinylidenechloride) fibre tray, a compatible plastic lid- forming film and suitable packaging machinery. Two packaging machinery sys- tems have been developed: a special semi-automatic table-top machine for small processors and a modified Tiromat (Kramer&Grebe) vacuum-forming machine for large processors. The fibrelam packages are claimed to be cheaper than plas- tic trays. The supplier is Keyes Fibre/Maidstone Machine Co. in UK. The system can be applied to meat, poultry, cooked meats, fruit, vegetables, bakery products, salads and ready meals.
3.6. Bag-in-carton systems
The Hermetet system supplied by Akerlund&Rausing is probably one of the best known. The packages are consumer size for dry powders and granules, such as coffee, tea and dried potato powder. The air from the package is removed by a vacuum, after which the package is gas flushed.
3.7. Bag-in-box system
The product is loaded into a barrier or non-barrier bag. It can be in bulk or in con- ventional EPS trays with film over-wrap. The machine inserts two snorkels into the top of the bag, creates a vacuum and gas flush (figure1). The system has the advantage that a conventional unit pack can be produced and then gas-flushed.
The suppliers are e.g. CVP, Corr-Vac, Snorkel-Vac and Bernhardt. Only the Bernhardt machine operates automatically, the others are manually operated.
3.8. Walki-vent system
The system is based on pre-made laminate pouches with a vent and the use of CO2pellets, which start gassing as soon as the package is sealed. It is not neces- sary to feed gas into the package, and normal vacuum packaging equipment can be used. However, a special sealing tool is required to use the Walkivent system
on web-fed vacuum packaging machines, since the ventilator is formed in the heat seal. The purpose of the ventilator is to allow the excess pressure formed dur- ing the gasification of CO2pellets to escape. The system can be applied to raw meat, chicken and fish.
3.9. Flavaloc
Flavaloc is a system that has beeb developed in Australia. It is similar to the con- ventional gas package except that an intermediate web is introduced. This web is positioned between thermo-formed base and the top lidding web. The Flavaloc machine is similar in design to a standard in-line thermo-forming, filling and lid- ding packaging machine except that an additional gassing and sealing station is incorporated. This station is also equipped with a stretch-and-flange sealing head that stretches the intermediate web over the pack contents and seals it to a flange located on the side wall of the tray base. The Flavaloc station also evacuates the pack and introduces a predetermined gas mixture into the space between the thermo-formed base and the stretch web before sealing the web onto the base.
The second station gas flushes the pack above the stretch web and seals a lidding material onto the packs. Different gas mixtures can be introduced above and below the stretch web. The package is claimed to solve many of the problems, such as the deterioration in the appearance of the lid material during transporta- tion and handling, typically associated with the use of conventional gas packages comprising a thermo-formed tray and a heat-sealed lidding material. It has yet to be widely used commercially.