Managing frozen foods

296 Pages·2000·6.771 MB·English

by  Chris Kennedy

Managing frozen foods
Edited by
Christopher J. Kennedy
Published byWoodhead Publishing Limited, AbingtonHall, Abington
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Preface
AsIwritethispreface,theendofthesecondmillenniumisrapidlyapproaching.
Bythetime thistextisread,however,theexcitementofthemillenniumwillbe
longforgotten.Wewillallbebackatwork,endeavouringinourdifferentways
tosupplytheworld’sconsumerswithexcitingfrozenfoodproductsandtomake
aEurooradollartoliveonatthesametime.Ihopethisbookwillhelpusallto
meet those objectives.
ThebookwasbornoutofaconcertedactionthatwassponsoredbyDGXIIof
the European Commission, under the FAIR Programme of Framework V
throughresearchcontractFAIRCT96-1180.Theactionwasaimedatimproving
thepreservationofqualityandsafetyoffrozenfoodsthroughoutthedistribution
chain. The action brought together experts from industry and academia across
theEuropeanUnion.Wemettogetheratsixplenarymeetingsanddiscussedthe
many technical and scientific developments being made in the field of frozen
foods. The period of our meetings has coincided with a time of rapid
development in the industry and in our understanding of science related to the
freezing of foods.
From the beginning the emphasis of our action was to promote existing best
practice aswellastolooktothefuture.Weproducedanumberofbest-practice
guides for use by manufacturers and distributors as well as consumer
information leaflets. Our aim has been to write at a level that will be of use
to the professional food technologist or engineer working in the frozen food
industry. This is a philosophy that we have tried to follow in producing this
book. I hope we have been able to convey the essentials of frozen food
production from farm to freezer in an understandable and straightforward
manner.Ihopetoothatwehavebeenabletoprojectalittleinsightintowhatthe
future may hold for this industry.
x Preface
I wouldlike to thank the manypeople whohave helped in the production of
thisbook,particularlymyco-authorsfortheenthusiasticwayinwhichtheyhave
contributed. I should also like to thank Cathy Goundry who has spent many
hours reading and correcting our typographic errors and grammatical slips. Her
help during the editing of this book has been invaluable to me.
Christopher J. Kennedy
Contents
Preface .................................................................. ix
List of contributors ..................................................... xi
List of acronyms ....................................................... xv
1 Introduction ...................................................... 1
C. J. Kennedy, University of Leeds
2 Maintaining safety in the cold chain ............................ 5
L.Bogh-Sorensen,DanishVeterinaryandFoodAdministration,Søborg
2.1 Introduction .................................................. 5
2.2 Response of micro-organisms to freezing .................... 5
2.3 The main risks in the supply chain for frozen foods ......... 12
2.4 Techniques for microbiological analysis ..................... 16
2.5 Sampling ..................................................... 17
2.6 Effects of temperature abuse: viability and recovery ......... 20
2.7 Thawing techniques .......................................... 21
2.8 New developments in research ............................... 24
2.9 Summary: effective monitoring and product quality ......... 25
2.10 References ................................................... 26
3 Fruit and vegetables: the quality of raw material in relation to
freezing 27
A. Maestrelli, IVTPA, Milan
3.1 Introduction .................................................. 27
3.2 Factors affecting F&V cultivar selection suitable for
freezing ...................................................... 30
vi Contents
3.3 Technological factors ........................................ 33
3.4 Sensory factors .............................................. 37
3.5 Agronomic and technological aspects of potatoes for
freezing ...................................................... 39
3.6 Nutritional factors ........................................... 40
3.7 How to measure subjective and objective F&V quality
characteristics ................................................ 43
3.8 Future perspective of F&V cultivar selection for frozen
products ..................................................... 49
3.9 Summary .................................................... 51
3.10 Acknowledgements .......................................... 53
3.11 References ................................................... 53
4 The pre-treatment of fruits and vegetables ..................... 57
D. Torreggiani (IVTPA, Milan), T. Lucas (CEMAGREF),
A.-L. Raoult-Wack (CIRAD)
4.1 Introduction ................................................. 57
4.2 Blanching .................................................... 59
4.3 Partial dehydration and formulation techniques .............. 60
4.4 Future trends ................................................ 75
4.5 Summary .................................................... 75
4.6 References ................................................... 77
5 The pre-treatment of meat and poultry ......................... 81
S.J. James, FRPERC, Bristol
5.1 Introduction ................................................. 81
5.2 Influence of the live animal ................................. 83
5.3 Pre- and post-slaughter handling ............................. 86
5.4 New trends .................................................. 89
5.5 Summary .................................................... 90
5.6 References ................................................... 91
6 The selection and pre-treatment of fish ......................... 95
N. Hedges (Unilever Research, Sharnbrook) and
Jette Nielsen (The Danish Institute for Fisheries Research, Bygning)
6.1 Introduction to the freezing of fish .......................... 95
6.2 What are the elements of the frozen fish product supply
chain? ....................................................... 96
6.3 The freezing of fish ......................................... 97
6.4 Changes occurring on frozen storage ........................ 100
6.5 Pre-freezing factors that influence the quality of frozen
fish products ................................................. 103
6.6 The effect of freezing rate ................................... 106
6.7 The effect of temperature cycling ........................... 106
6.8 Summary .................................................... 106
Contents vii
6.9 References ................................................... 107
6.10 Further reading .............................................. 110
7 Factors affecting the stability of frozen foods ................... 111
N.E. Zaritzky, CIDCA, La Plata
7.1 Physical changes during freezing and frozen storage ......... 111
7.2 The chemistry of frozen foods ............................... 122
7.3 The impact of freezing on food quality ...................... 126
7.4 New trends in research ....................................... 130
7.5 Summary: maximising quality in the freezing processes ..... 132
7.6 References ................................................... 133
8 Freezing processed foods ......................................... 137
C. J. Kennedy, University of Leeds
8.1 Introduction .................................................. 137
8.2 Ready meals ................................................. 137
8.3 Bakery products .............................................. 143
8.4 Ice cream .................................................... 149
8.5 Bibliography ................................................. 157
9 Freezer technology ............................................... 159
J.P. Miller (Air Products plc, Basingstoke) and
C. Butcher (CopyWrite, Coventry)
9.1 Introduction .................................................. 159
9.2 Refrigeration systems ........................................ 160
9.3 Freezers ...................................................... 172
9.4 Choosing a freezer ........................................... 189
9.5 Further reading .............................................. 193
10 Selecting packaging for frozen food products.................... 195
M. George, Campden and Chorleywood Food Research Association,
Chipping Campden
10.1 Introduction .................................................. 195
10.2 Essential requirements for frozen food packaging ............ 196
10.3 Legislative responsibilities ................................... 200
10.4 Types of packaging material ................................. 202
10.5 Assessing the suitability of packaging materials for different
products ...................................................... 204
10.6 Packaging machinery ........................................ 206
10.7 Future developments in frozen food packaging .............. 207
10.8 Summary: how packaging can maximise product quality .... 210
10.9 References ................................................... 210
10.10 Further reading .............................................. 211
viii Contents
11 Storing frozen food: cold store equipment and maintenance .. 213
R. Fuller, Consultant
11.1 Storage, shelf-life and product quality ....................... 213
11.2 Cold store design ............................................ 214
11.3 Detail design features ........................................ 221
11.4 Monitoring and recording product conditions ................ 225
11.5 Good operating practice ..................................... 226
11.6 New developments .......................................... 230
11.7 Summary .................................................... 231
11.8 References ................................................... 231
11.9 Further reading .............................................. 232
12 Retail display equipment ........................................ 233
G. Cortella (University of Udine) and
F. Polonara (University of Ancona)
12.1 Introduction ................................................. 233
12.2 Design of display cabinets ................................... 234
12.3 Variations for different product types ........................ 245
12.4 Installation ................................................... 245
12.5 Operation, monitoring, maintenance and breakdown ......... 248
12.6 New developments .......................................... 251
12.7 Legislative issues ............................................ 254
12.8 Summary .................................................... 257
12.9 Acknowledgements .......................................... 259
12.10 References ................................................... 259
13 Future trends in frozen foods ................................... 263
C. J. Kennedy, University of Leeds
13.1 Introduction ................................................. 263
13.2 Consumers will want more frozen foods – markets .......... 264
13.3 Frozen foods will be more nutritious ........................ 265
13.4 Ice crystals will be smaller: controlling ice nucleation ...... 266
13.5 And they will stay smaller: controlling ice crystal growth ... 269
13.6 The frozen food chain will be controlled more effectively .. 273
13.7 We will have wider choice and better display when we go
shopping ..................................................... 275
13.8 If we go shopping at all ..................................... 276
13.9 Summary .................................................... 276
13.10 Bibliography ................................................. 277
Index ............ ...................................................... 279
1
Introduction
C. J. Kennedy, University of Leeds
A culinary revolution lies largely unnoticed within the domestic freezers of
Western households. The growth of the frozen food market has continued
unabated for over 70 years since Clarence Birdseye sold the first plate
freezer. Theageoffrozenfoodsasacheapandconvenient ‘junk’foodhave,
however, passed. Frozen foods are becoming high quality added-value
products and are making their presence felt in almost all sectors of the food
market.
To compete in this modern food market the manufacturer needs to provide
productsfor an increasingly educated consumer.Consumer awarenessof issues
relating to nutrition and food safety has never been higher and new
developments in these fields are rapidly brought to their attention through the
media. Moreover,awarenessofthe culinary opportunitiesof‘exotic’meals and
designer foods has added an element of fashion to the popularity of many food
products. To meet the demands and expectations of this market therefore
requiresanever-changingrangeofproductsandtechniques.Tostopswimming
is to be carried away by the tide.
The frozen food industry has many advantages over the chilled and fresh
sectors in addressing consumer expectations. Low temperatures necessarily
result in higher stability and provide an intrinsic advantage, if properly
exploited, in bringing nutritionally high value foods to the consumer. The
freezing ofvegetablesafterharvest,forexample,willguaranteetheconsumera
higher vitamin C content than could be attained by any other form of
preservation and distribution. Furthermore frozen foods have always enjoyed a
safety record second to none since, if properly handled before freezing and
during distribution, there is no possibility of the growth of microbial
contaminants between freezing and thawing.