In-Pack Processed Foods

Improving Quality

P Richardson

• Publisher: Woodhead Publishing
• Year: 2008
• Print ISBN: 9781845692469
• eBook ISBN: 9781845694692
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Recent developments have enabled the production of in-pack processed foods with improved sensory quality as well as new types of heat-preserved products packaged in innovative containers. This book reviews these advances in packaging formats and processing technologies and their application to produce higher quality, safer foods.Opening chapters cover innovative can designs and non-traditional packaging formats, such as retort pouches. The second part of the book reviews the developments in processing and process control technology required by newer types of packaging. Part three addresses the safety of in-pack processed foods, including concerns over pathogens and hazardous compounds in processed foods. The book concludes with chapters on novel methods to optimise the quality of particular types of in-pack processed foods such as fruit and vegetables, meat, poultry and fish products.In-pack processed foods: improving quality is a valuable reference for professionals involved in the manufacture of this important group of food products and those researching in this area. - Reviews advances in packaging formats and processing technologies - Covers innovative can designs and non-traditional packaging formats - Examines the safety of in-pack processed foods, including concerns over pathogens

Part I

Advances in packaging formats for in-pack processed foods

Outline

Chapter 1: Advances in can design and the impact of sterilisation systems on container specifications

Chapter 2: Retortable pouches

Chapter 3: Improving the performance of retortable plastics

Chapter 4: Advances in sealing and seaming and methods to detect defects

1

Advances in can design and the impact of sterilisation systems on container specifications

G. Pape, Crown Packaging UK plc, UK

Publisher Summary

The cans of today are much different in construction to those of the early 1900s when canning was in its infancy, but they have to provide the same functionality. Environmental and economic factors continue to challenge the can design engineers. The market for food containers is driven by innovation, whatever the material of choice. Can design continues to rise to this challenge by progressively using lower gauge materials to achieve the same can and end performance. There is a point at which innovative design cannot go forward without the sign-on of the canners. It has become apparent over recent years that the hurdles to introduction of innovative metal packaging lie not only in the domain of the can manufacturer, but now also include hurdles in the cannery, often focused around can handling, but also challenged by the sterilization systems themselves. The can has changed significantly in the last 20–30 years; thus can designs of today are still expected to perform in equipment installed a generation ago. This chapter provides an understanding of how the can designs of today are able to perform well when sterilized through systems that are in use in the canneries today, whatever their vintage and reviews these key questions: (1) “What influences can performance?” and (2) “How are can performance requirements determined?” It illustrates the challenges that face the can designers of today employing a series of case histories.

1.1 Introduction

A significantly large majority of ambient shelf-stable food products rely on the metal can to provide a robust container that has an outstanding safety record stretching back many decades. The cans of today are much different in construction to those of the early 1900s when canning was in its infancy, but they have to provide the same functionality. They must:

• be heat processable to allow achievement of commercial sterility,

• have integrity which prevents bacterial ingress after heat processing,

• provide a total oxygen barrier to minimise degradation of the product inside,

• resist handling abuse during distribution and retailing,

• be easy to open for the consumer, and

• in today’s environmentally sensitive world be recyclable as a primary material.

The metal can, whether manufactured from steel or aluminium, performs all of these functions well. However, environmental and economic factors continue to challenge the can design engineers. The market for food containers is driven by innovation, whatever the material of choice. Can design continues to rise to this challenge by progressively using lower gauge materials to achieve the same can and end performance. This ensures that the key criteria for the package outlined previously are not compromised. There is a point at which innovative design cannot go forward without the sign-on of the canners.

It has become apparent over recent years that the hurdles to introduction of innovative metal packaging lie not only in the domain of the can manufacturer, but now also include hurdles in the cannery, often focussed around can handling, but also challenged by the sterilisation systems themselves. Large canneries sterilise the bulk of their output through large continuous cooker systems, such as hydrostats, and reel and spiral cookers. These cookers provide high efficiency but they are limited in their capabilities. Economy of scale also means that they are costly to install and have a long service lifetime, often 20–30 years. The can has changed significantly in the last 20–30 years; thus can designs of today are still expected to perform in equipment installed a generation ago.

In order to understand how the can designs of today are able to perform well when sterilised through systems which are in use in the canneries today, whatever their vintage, this chapter will seek to review the following key questions:

• What influences can performance?

• How are can performance requirements determined?

A series of case histories will be employed to illustrate the challenges which face the can designers of today.

1.2 The influence of sterilisation systems on container specifications

A number of simple questions often arise in the debate to determine what container specification may be used for a new business opportunity. Classically, the first question of the marketeer is:

• What is the optimum specification for packing product X for customer Y in cannery Z?

The commercial and technical team will then ask:

• Why can we use specification A for this application at canneries X and Y, but not at cannery Z?

The manufacturing team might ask:

• Are we able to reduce the end peaking performance for diameter B? and:

• If we optimise the can and/or end performance, what are the limitations?

Having taken these questions onboard, we need to understand what are the driving forces behind these questions.

For the packaging manufacturer there is a desire to supply a minimum portfolio of specifications to limit manufacturing line changeovers. A reduced portfolio will allow more cost-effective material purchasing with fewer specifications required. Also, it is more cost effective to operate with a minimum inventory using just-in-time manufacturing to limit working capital. Ideally, a ‘one specification fits all’ philosophy gives the most cost- and material-efficient solution, but will this solution meet the requirements of the canner ?

For the canner, the can must function on current can filling lines with heat processing achieved through existing sterilisation equipment and have cost-effective packaging specifications.

Fundamental to being able to provide a can design solution to these requirements is an understanding of the factors that might be influencial in affecting can performance:

• Fill level – Extremes of fill level/associated pack headspace will affect performance requirements. The headspace is the part of the can not filled with product. It is conventionally measured on an open can from the top of the can flange on an unseamed can, or from the top of the double seam on a seamed can.

• Fill temperature – High and low temperatures of the solid or liquid phase components of a product recipe will have an effect. A high level of a cold garnish component on a soup pack can affect the initial pack temperature significantly.

• Can style – Depending on materials and profiles, a two-piece can base will have more/less volume expansion capability than a classic/sanitary end used on a three-piece can. Can base and end profiles may be flexible or rigid, depending on the design brief, and may significantly influence the level of internal pressure generated in the can.

• Steriliser system – Batch overpressure retort systems offer significant flexibility in their temperature and pressure capability, compared with the rigidity of capability of these parameters in continuous hydrostat or reel and spiral cooker systems, or in batch steam retorts.

How are these factors understood ?

In the past it was only possible to carry out pilot-plant simulations with pressures in the packs measured using conventional wired pressure transducers. The limitations of these systems were generally governed by the ability of the electronic components and wiring to withstand sterilisation in steam at temperatures typically up to 140 °C.

Systems were available that used silicone oil-filled capilliary tubes to connect to a pressure transducer positioned outside of the steam environment; however, the nature o...

Table of contents

• Cover image
• Title page
• Table of Contents
• Related titles:
• Copyright
• Contributor contact details
• Preface
• Part I: Advances in packaging formats for in-pack processed foods
• Part II: Advances in processing technology
• Part III: Safety of in-pack processed foods
• Part IV: Improving the quality of particular in-pack processed products
• Index