Handbook of Seal Integrity in the Food Industry (eBook)

Michael Dudbridge (Autor)

eBook Download: EPUB

2016
John Wiley & Sons (Verlag)
978-1-118-90459-6 (ISBN)

Infos

Seal integrity is vital in food supply chains with modern methods of food retailing and a requirement for very high levels of consumer satisfaction. Robust packages are an important factor in food preservation, consumer confidence in the product as well as waste minimisation and cost control throughout the system.

The Handbook of Seal Integrity in the Food Industry is aimed at people working in food supply chains and associated industries from packing machine operators to quality managers and from retail technical staff to packaging machine designers and maintenance engineers. This well illustrated and comprehensively indexed handbook paints a complete picture of all of the factors that operate together in the creation of food packages with high performing seals.

A comprehensive review of the reasons for poor seal integrity is included along with suggestions for improvements in maintenance, machine set up and operation. Seal testing systems are featured along with management techniques to ensure a high level of performance and consistency in your business and a ?right first time? approach within packaging systems. The design and operation of the main types of sealing system is reviewed for rigid, semi rigid and flexible packaging systems along with an overview of packing materials such as thermoplastics.

Finally the handbook looks at innovations in the packaging of food products with a view of developments in packaging materials, sealing systems and on-line seal integrity measurement and monitoring systems.

Autor

Michael Dudbridge has managed food manufacturing operations for major companies throughout his career. Roles have included factory operations and quality management as well as engineering and continuous improvement responsibilities.

Textauszug

CHAPTER 1
Overview of sealing technologies, formats and systems

1.1 Introduction

This chapter provides a basic grounding in the principles of sealing a product inside a package. It includes the principles of making a seal using heat, ultrasonic energy and other sealing systems such as cold sealing using adhesives. This chapter also includes considerations of the chemistry of the materials being sealed together and how the sealing system must be designed and operated in a way that is compatible with the physical and chemical properties of the materials and also the product to be packaged.

This chapter also includes an overview of the various packaging system options available in the food industry such as bag making, pouch sealing, tray sealing, flow wrapping and form fill seal systems. These packaging options are included in much greater detail elsewhere in the book.

Finally, the chapter reviews the industry sectors that routinely use sealing technologies in their packaging processes – pharmaceuticals, food and other consumer products – and their need for pack security, shelf life extension and product protection from contamination and loss. Though the focus of the book is the food industry, the principles of sealing products into packages can be applied across many different industries.

1.2 The importance of packaging and seal integrity

Modern methods of retailing, especially food retailing, rely in the main on the shopper selecting pre-packaged products from the shelves of the retailer. It is vital that the food inside the package is protected from spoilage and leakage by the packaging that is surrounding it. Leaking packs on a supermarket shelf are an indication of a lack of control in the production factory and this will cause shopper rejection of the pack and waste throughout the supply chain. If a leaking pack is inadvertently placed in the shopping basket then it may well generate a consumer complaint or in the worst case it may cause illness in the consumer.

Without robust packaging capable of withstanding the rigours of logistics and retail display the whole way that we shop for food and other consumer goods would not be possible. It is vital that factories supplying packaged goods understand the needs of the product and the needs of the consumer in terms of the package (Fig. 1.1).

Fig. 1.1 Modern methods of food retailing rely on pre-packaged goods being available for the shopper to select. The packaging and seal integrity are important factors in the selection process as are the distribution and safety of the foods in the shops. The extended shelf life that is offered by the packaging system is vital to the way that our food distribution systems work, making a wide variety of foods available to consumers.

There are many packaging materials, and systems and methods have been designed to use these materials to create packages to enclose, protect and retain the contents of the pack. Recent trends in packaging materials have moved away from rigid materials such as metal cans and glass jars towards semi-rigid and flexible materials such as thermoplastics. Sealing of rigid packaging is usually obtained using mechanical seals such as the double seam used in the canning industry or the screw cap in glass jars. The sealing of semi-flexible and flexible materials requires a bond between the layers to join them together. This bond is most commonly created by the controlled application of heat to the materials, but other options are available as will be explored later.

1.3 The sealing of rigid containers

Both metal cans and glass jars rely on two factors to create a strong seal. First, there is a need of a mechanical fix to join the can to the can end or the glass jar to its lid. This mechanical fix is created by bending and forming the rigid materials after filling to prevent the can end or jar lid from separating from the body of the package. This is not enough to create a seal though. The small gaps that appear in these mechanical fixes would allow the passage of oxygen and bacteria both into and out of the pack as well as possible leakage of product. The small gaps need to be filled to ensure that contamination or leaking cannot occur. This is achieved using flexible mastics, rubber-like materials that can move and distort their shape during the making of the mechanical fix so that the small gaps can be filled. This creates a hermetic seal – one where nothing can pass into or out of the pack (Fig. 1.2 and Fig. 1.3).

Fig. 1.2 A double seam on a canned product where the mechanical strength of the material is used to hold the parts together. The small gaps are filled with a flexible mastic compound.

Fig. 1.3 A glass jar with a twist lid is a common package. Again, the strength is given by the materials, with the final seal being obtained using a flexible compound inside the lid.

1.4 Hermetic seals

Hermetic seals are required when packaging foods with a long shelf life. These foods are often termed ‘shelf stable’ and have their long shelf life even when stored in ambient, non-refrigerated, conditions. The food inside the hermetically sealed packs is often heat-processed after the packs are sealed to kill any bacteria inside the pack. This heat process is carried out in large pressure cookers, called retorts, where the packs are taken up to 120°C. This process is very demanding on the packaging. The combination of heat and pressure inside the retort means that the seals have to be very strong to withstand the process. The rigours of this process continue after the heating stage. During cooling any leak in the seal would see the can or jar suck the cooling water into the container, and with the cooling water could come bacteria and other contaminants. The development of this ‘canning process’ has been rigorous and the systems and package designs have been optimised to make the process as efficient as possible without risking the food safety of the products.

1.5 Developments in the canning process

In order to reduce the cost of the canning process there have been many changes. Each change is tested to ensure that the safety of the foods is not compromised as the efficiency of the process is improved. Many of the optimisation techniques used in rigid container packing systems have been repeated with semi-flexible and flexible packaging system, so the themes will be seen again later in this book but applied to a different set of circumstances.

1.5.1 Thinner materials

Glass and metal are expensive materials from which to construct a food container, and as a result of this cost packages have been redesigned with less material and thinner walls, but importantly the designs retain, or even improve, the pack strength. Clever design and careful analysis has removed excess material from where it is not needed and as a result the cost of the package has been reduced without any deterioration of the pack performance (Fig. 1.4).

Fig. 1.4 Thinner materials used to reduce the cost of a package. In this can the wall thickness was reduced but the side wall strength was retained using the beaded shape, resulting in a lower cost can that performs well.

1.5.2 New materials

Changes in sealing mastic materials have improved performance as has the lining material on the inside of metal rigid containers. Changes here have seen improved performance especially in resisting the effects of acid foods that can attack the materials during the shelf life of the product long after the food containers have left the factory.

1.5.3 Additional protection of the container from secondary packaging

Glass containers have become thinner as designers seek to reduce the package weight and this has, in some circumstances, caused an increase in damage to packages during logistics and retail display. Systems such as shrink sleeve labelling have allowed the new low-weight container to be retained because of the extra protection offered by the secondary package (Fig. 1.5).

Fig. 1.5 The use of shrink labels adds a layer of protection to glass bottles with thinner walls.

1.6 Heat sealed packages

Semi-rigid and flexible packaging materials have the advantage over rigid packaging materials because of their low weight and low cost but they have a distinct disadvantage when it comes to sealing them to make a container. Because of their flexibility a mechanical fix for the package is not possible. To seal semi-rigid and flexible packages a different method of sealing must be adopted. The materials of the package must be bonded together to create a seal (Fig. 1.6).

Fig. 1.6 Flexible materials have been made less expensive by a process of ‘down gauging’ or making thinner. If this process has not been done correctly then the performance of the pack can be affected in terms of seal integrity or strength. This thinner film has had eye marks added to allow the packing machine to compensate for the extra stretch that now occurs.

Semi-rigid trays for ready meals and flexible bags for snack foods have to be sealed in order to retain the product and protect it from contamination or leakage. The seal needs to be able to carry out its function during...

Produkt-Details

• Erscheint lt. Verlag: 22.2.2016
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Biologie
• Themenwelt: Technik ► Lebensmitteltechnologie
• Themenwelt: Wirtschaft ► Betriebswirtschaft / Management
• Themenwelt: Weitere Fachgebiete ► Land- / Forstwirtschaft / Fischerei
• Schlagworte: Business & Management • food complaints • Food Packaging • Food Science & Technology • food spoilage • Food waste • heat seals • Industrial Engineering • Industrial Engineering / Quality Control • Industrielle Verfahrenstechnik • leaking packs • leaking seals • leaking trays • Lebensmittelforschung u. -technologie • Lebensmittel / Verpackung • Production Operations Management • Produktionssteuerung • Qualitätssicherung i. d. Industriellen Verfahrenstechnik • Qualitätssicherung i. d. Industriellen Verfahrenstechnik • seal integrity • seal testing • seal training • Wirtschaft u. Management
• ISBN-10: 1-118-90459-1 / 1118904591
• ISBN-13: 978-1-118-90459-6 / 9781118904596