Principles and Applications of Modified Atmosphere Packaging of Foods

Modified atmosphere packaging (MAP) has proved to be one of the most significant and innovative growth areas in retail food packaging of the past two decades. Bulk modified atmosphere packs have been an accepted form of packaging for meat and poultry in the USA since the early 1970s, but MAP is only now of being widely adopted. Today there is a substantial wholesale on the verge market for bulk packaged fresh vegetables and fruit, and the most significant retail MAP products are fresh pasta, pre-cooked poultry and sausage, and biscuits (a unique American product). The United Kingdom is the biggest single market for the modified atmosphere packaging of fresh chilled food products, accounting for about half of the total European market. A further quarter is represented by France. The success of MAP in both the British and French markets can be attributed to the large, highly sophisticated food retailing multiples and dense populations existing in both countries.

1 Introduction.- 1.1 Historical background.- 1.2 Definitions, terminology and abbreviations.- 1.2.1 Modified atmosphere packaging (MAP).- 1.2.2 Controlled atmosphere packaging (CAP).- 1.2.3 Gas packaging.- 1.2.4 Vacuum packaging (VP).- 1.2.5 Gas cocktail.- 1.2.6 Controlled atmosphere storage (CAS).- 1.2.7 Hypobaric storage.- 1.3 Methods of atmosphere modification in packaged foods.- 1.3.1 Vacuum packaging.- 1.3.2 Gas packaging.- 1.4 Gases used in MAP.- 1.4.1 Oxygen (O2).- 1.4.2 Carbon dioxide (CO2).- 1.4.3 Nitrogen (N2).- 1.4.4 Carbon monoxide (CO).- 1.4.5 Other gases.- 1.4.6 Gas mixtures.- 1.4.7 Sources of gases.- 1.5 Microbiology of MAP.- 1.5.1 Effects on spoilage microorganisms.- 1.5.2 Effects on pathogenic microorganisms.- 1.5.3 Storage temperatures.- 1.6 Advantages and disadvantages of MAP.- 1.6.1 Advantages of MAP.- 1.6.2 Disadvantages of MAP.- References.- 2 The market.- 2.1 Introduction.- 2.2 History of controlled atmosphere/modified atmosphere/vacuum packaging.- 2.3 Europe.- 2.3.1 Fresh meats.- 2.3.2 Fresh vegetables.- 2.3.3 Prepared foods.- 2.4 United States/Canada.- 2.4.1 Red meat.- 2.4.2 Poultry.- 2.4.3 Fruit and vegetables.- 2.4.4 Soft bakery goods.- 2.4.5 Pasta.- 2.4.6 Pizza.- 2.4.7 Salads.- 2.4.8 Other products.- 2.5 Conclusion.- Further reading.- 3 Packaging machinery.- 3.1 Historical development.- 3.2 Gases.- 3.3 Packaging material.- 3.4 Packaging machines.- 3.5 Chamber machines.- 3.5.1 Thermoforming system.- 3.5.2 Preformed container machines.- 3.6 Flexible pillow wrapping machines.- 3.6.1 Horizontal form-fill-seal machine systems.- 3.6.2 Inverted horizontal form-fill-seal machine systems.- 3.6.3 Vertical form-fill-seal systems.- 3.7 Fail-safe assurance.- 3.8 Automatic product feeding systems.- 3.9 Conclusion.- Appendix―Packaging systems for MAP.- 4 Films for MAP of foods.- 4.1 Introduction.- 4.2 Plastic films commonly used in MAP.- 4.2.1 Low density polyethylene (LDPE).- 4.2.2 Linear low density polyethylene (LLDPE).- 4.2.3 High density polyethylene (HDPE).- 4.2.4 Polypropylene (PP).- 4.2.5 Ionomers.- 4.2.6 Ethylene vinyl acetate copolymer (EVA).- 4.2.7 Polyvinyl chloride (PVC).- 4.2.8 Polyvinylidene chloride (PVdC) copolymer.- 4.2.9 Polystyrene (PS).- 4.2.10 High impact polystyrene (HIPS).- 4.2.11 Barex.- 4.2.12 Polyamides.- 4.2.13 Polyethylene terephthalate (polyester or PET).- 4.2.14 Ethylene vinyl alcohol (EVOH) - trade name EVAL.- 4.2.15 Coextruded orientated polypropylene (COPP).- 4.2.16 Other films.- 4.3 Combinations of films.- 4.3.1 Laminates, coextrusion and extrusion coating.- 4.3.2 Specifications.- 4.4 Typical specifications for MAP use.- 4.4.1 Horizontal and vertical form-fill-seal systems.- 4.4.2 Bulk gas packaging (BGP).- 4.4.3 Microwavable packs.- 4.4.4 Technical problems.- 4.5 Seal system and quality.- 4.5.1 Peelable seals.- 4.5.2 Antifog (AF) properties.- 4.5.3 Printing and labelling.- 4.5.4 Specifications.- 4.6 Legislation and the environment.- 4.7 Oil use and energy.- Appendices.- Appendix I Antifogging properties.- Appendix II Draft specification for CAP reels.- Appendix III Recommended storage conditions for CAP materials.- Appendix IV Calculations.- Reference.- 5 Quality control of MAP products.- 5.1 Introduction.- 5.2 Safety and quality of MAP foods.- 5.3 Applications of hazard analysis critical control point (HACCP) to MAP foods.- 5.4 Total quality control and quality of MAP foods.- 5.5 Combining hazard analysis critical control point and total quality control.- 5.6 Quality control testing.- 5.6.1 Film faults.- 5.6.2 Headspace gas analysis.- 5.6.3 Seal strength.- 5.6.4 Temperature checks.- 5.7 Regulatory aspects of MAP foods.- 5.8 Summary.- References.- 6 Fruit and vegetables.- 6.1 Introduction.- 6.1.1 Controlled atmosphere storage vs. MAP.- 6.1.2 Advantages and disadvantages of MAP.- 6.1.3 Methods of creating modified atmosphere conditions.- 6.1.4 Optimal equilibrium gas levels.- 6.2 Background information.- 6.2.1 Factors affecting shelf-life.- 6.2.2 Intrinsic properties of fresh produce.- 6.3 Extrinsic factors to optimise.- 6.3.1 Harvesting.- 6.3.2 Handling.- 6.3.3 Hygiene.- 6.3.4 Temperature.- 6.3.5 Water loss and relative humidity (RH).- 6.3.6 Packaging materials.- 6.3.7 Packaging machinery.- 6.3.8 Gas/product ratio.- 6.3.9 Light.- 6.4 Mathematical modelling of MAP.- 6.5 Future research needs.- 6.6 Conclusions.- References.- 7 Bakery products.- 7.1 Introduction.- 7.2 Food spoilage.- 7.3 Storage problems.- 7.3.1 Physical (i.e. staling).- 7.3.2 Chemical rancidity.- 7.3.3 Microbial spoilage.- 7.4 Mould spoilage.- 7.4.1 Economic losses.- 7.4.2 Types of mould.- 7.4.3 Factors influencing mould growth.- 7.5 Methods of preventing/controlling mould spoilage.- 7.5.1 Ultraviolet light.- 7.5.2 Infrared radiation.- 7.5.3 Microwave.- 7.5.4 Aseptic packaging.- 7.5.5 Antimicrobials.- 7.6 Packaging.- 7.6.1 Gas composition.- 7.6.2 Films.- 7.6.3 Packaging equipment.- 7.7 Effect of MAP on bakery products.- 7.8 Secondary spoilage of bakery products.- 7.9 Other methods of atmosphere modifications.- 7.9.1 Oxygen scavengers.- 7.9.2 Ethanol vapours.- 7.10 Economic analysis of MAP for bakery products.- 7.10.1 MAP benefits and costs.- References.- 8 Miscellaneous applications.- 8.1 Dairy products.- 8.1.1 Cheeses.- 8.1.2 Yoghurt.- 8.1.3 Milk.- 8.1.4 Milk powders.- 8.2 Ready meals.- 8.2.1 Gas mixtures.- 8.2.2 Temperature.- 8.2.3 Packaging operation and packaging materials.- 8.2.4 The market-place.- 8.2.5 Safety concerns.- 8.3 Coffee.- 8.3.1 Whole beans.- 8.3.2 Ground coffee.- 8.3.3 Instant coffee.- 8.4 Snacks.- 8.4.1 Nuts.- 8.4.2 Crisps and other snacks.- 8.5 Delicatessen/multi-component products.- 8.5.1 Sandwiches.- 8.5.2 Dressed salads.- 8.5.3 Breaded and batter-coated products.- 8.5.4 Pastry-based products.- 8.6 Beverages.- 8.7 Use of MAP in combination with other processes.- References.- 9 Fish.- 9.1 Introduction.- 9.2 Spoilage of fish.- 9.2.1 Effects of temperature on fish spoilage.- 9.2.2 Measurement of spoilage.- 9.2.3 Hazards associated with stored fish.- 9.3 Gaseous preservatives used in modified atmosphere storage of fish.- 9.3.1 Properties of the principal components.- 9.3.2 Proportions of gases recommended for use in MAP.- 9.3.3 Vacuum packaging (VP).- 9.4 Changes occurring during storage of fish products in MAP.- 9.4.1 Composition of the headspace gas mixtures.- 9.4.2 Effect of MAP on the pH of fish products.- 9.4.3 Bacteriological changes.- 9.4.4 Effects of MAP on microbiological hazards.- 9.4.5 Sensory properties.- 9.4.6 Effects of temperature rises on MAP products.- 9.4.7 MAP and chemical indices of fish spoilage.- 9.4.8 Residual effects.- 9.4.9 Fish products in bulk modified atmosphere packages.- 9.5 Adjuvant treatments.- 9.5.1 Chemical additives.- 9.5.2 Physical treatments.- 9.6 Conclusion.- References.- 10 Meat products.- 10.1 Introduction.- 10.2 Gases used in MAP of meat products.- 10.2.1 Oxygen.- 10.2.2 Nitrogen.- 10.2.3 Carbon dioxide.- 10.2.4 Experimental use of other gases.- 10.2.5 Gas mixtures.- 10.3 Important considerations.- 10.3.1 Safety.- 10.3.2 Temperature control.- 10.3.3 Oxygen permeability.- 10.3.4 Cured colour stability.- 10.3.5 Water activity (aw,), pH and microbial spoilage.- 10.4 Effects of MAP on selected meat products.- 10.4.1 Bacon.- 10.4.2 Beef jerky.- 10.4.3 Cooked beef roasts.- 10.4.4 Ground beef patties.- 10.4.5 British fresh sausages.- 10.4.6 Cooked meat loaves.- 10.4.7 Frankfurters.- 10.4.8 Ham.- 10.4.9 Meat pies.- 10.4.10 Pastrami.- 10.4.11 Wieners in natural casings.- 10.4.12 Poultry products.- 10.4.13 Cook-chill systems.- 10.4.14 Sous-vide cook-chill systems.- 10.5 The future.- References.- 11 Modified atmosphere storage of fresh meat and poultry.- 11.1 Introduction.- 11.2 Modified atmosphere packaging of red meats.- 11.2.1 Properties of red meat.- 11.3 Principles of packaging.- 11.4 Packaging films.- 11.5 Wholesale marketing.- 11.5.1 Vacuum packaging.- 11.5.2 Carbon dioxide.- 11.6 Retail marketing.- 11.6.1 Consumer cuts.- 11.6.2 Conventionally overwrapped trays.- 11.6.3 MAP.- 11.7 Modified atmosphere storage of poultry.- 11.8 Safety aspects of MAP.- References.