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Food Service
Systems
Carmel Lazarus
Nutrition Manager & Consultant Dietitian
Email: [email protected] Ph: 0416482199
February 2008
Objectives
Understand the different types of food
production and distribution systems
Recognise the different cook chill systems
available
Understand the advantages and
disadvantages of different production and
distribution systems
University of Sydney
Acknowledgements: Karen Walton/Associate Professor Peter Williams/Maria
Kokkinakos
Cook Fresh, Cook/Hot hold,
Cook Serve
Food Service Systems
Foods are prepared > Held for a short time > Served
Williams, PG. Journal of the American Dietetic Association 1996;
96(5): p491
Cook Fresh
Advantages
‘In house’ quality
control
Less specialised
equipment
Less prepared
storage
Regional buys
Disadvantages
Daily, busy meal
times
Workloads vary
Production occurs
over the whole day,
every day
Cook Chill
Foods are prepared > Chilled > Hot or Cold
Plating/Retherm
Salads, sandwiches, fresh/cold dairy desserts
also in cook chill systems
Advantages
Uniform workflow
Menu variety
Reduced
production costs
5 day production
Area wide menus
Quality control
Disadvantages
Specialised
equipment
Storage requirements
Some recipes aren’t
suited
Some foods not
suitable - grills
1
Equipment
Equipment
Long shelf life
Short shelf life
Cook Chill
Cook Chill
Cook Chill Delivery Systems
Food Service Systems
(Bulk heating, hot plating)
Cook Chill
(Cold plating,
retherm)
retherm)
Williams, PG. Journal of the American Dietetic Association 1996;
96(5): p491
2
Food service systems in NSW
hospitals (%)
Cook Freeze
Foods are prepared > Frozen >
Hot or Cold Plating/Retherm
Disadvantages
Advantages
As for cook chill
As for cook chill
Recipe modification
re: thickeners
Thawing step
1984
1993
2001
(n=270)
(n=179)
(n=93)
Cook fresh
93
81
54
Cook-chill
- external
- internal
5
18
6
12
42
29
13
Combination
2
1
5
Mibey R, Williams P. Food Service Technology 2002; 2:95-103
Food service systems in NSW
hospitals (%)
System
1993
All
2001
All
2001
<100 beds
2001
100beds +
Cook fresh
81
54
77
29
Ext Cook chill
6
29
11
47
Int Cook chill
12
13
9
16
Combination
1
5
4
9
Total
100
100
100
Manager’s satisfaction with their
foodservice system Mean rating
(1 = very dissatisfied; 10=very satisfied)
100
Mibey R, Williams P. Food Service Technology 2002; 2:95-103
Location
Centralised
96
2001
All
89
2001
<100 beds
2001
100+ beds
91
87
Cook Fresh
Cook Chill
0-24
8.7
8.0
25-49
8.0
7.1
50-99
8.3
6.2
100-249
7.9
5.6*
250+
7.0
5.8
All
8.1
5.9**
Mibey & Williams Food Service Technology 2002;2:95-103
Meal delivery systems
% NSW hospitals 2001
Meal plating location – % NSW
hospitals
1993
All
Hospital size
(beds)
Hot delivery systems
Insulated cover and base
34.5
Heated pellet
20.9
Plate cover only
14.3
Hot and cold delivery cart
4.7
Heated bulk food trolleys
1.9
Total
79.1
Chilled or Frozen systems
Decentralised
4
11
9
Mibey & Williams Food Service Technology 2002;2:95-103
13
Convection ovens
10.5
Infra-red ovens
4.8
Microwave ovens
3.8
Conduction heating
1.9
Total
21.0
Mibey & Williams Food Service Technology 2002;2:95-103
3
Distribution Systems
St Vincent’s Campus
Delivered in Bulk heated using
a van
Plated on Site
Hot metal
Wax pellet in base
Insulated plate base & cover
Insulated tray
Trolley cart with heat/refrigeration
Delivered in bulk
Palliative care & Rehab Plated on site
Mental Health
Delivered in Bulk Heated
Plated on site
SVPH Kitchen
Delivered in Bulk (heated)
Plated on site
Public Hospital
Centralised Plating
Centrally plated
Delivered in heated and
Refrigerated trolleys
Bulk food in chilled/heated trolleys
Bulk food in insulated containers
Frozen/chilled food distributed
D&A
Distribution Systems cont.
Decentralised Plating
Centralised System
Advantages
Semi centralised – food plated centrally and
distributed for reheating
Central tray setting
Decentralised heating
Specialised Trolleys
Disadvantages
Decentralised System
More pressure on staff at meal periods
Must stagger meal hrs
Issues with communication between ward and kitchen
Physical location of some wards impacts on meal aesthetics
Trends
Advantages
Improve motivation/job satisfaction as FS personnel closer to consumer
consumer
Allows last minute changes if food plated in bulk, not for preplated meals
Breaks job tasks down into smaller units so easier to cope with
Labour saving
Allows meal checking/staff supervision
Economies of space and equipment
Saving in overheads – maintenance, fuel, cleaning
Allows batch cooking
Reduced food waste
Reduced noise on wards
Improve menu variety
Disadvantages
Difficult to supervise
Food wastage
Possible reduction in quality if distributed hot/Physical
location of some wards impacts on meal aesthetics
Outsourcing Food Production
Room Service
Retail Outlets in Hospitals
McCafe RPAH,
Gloria Jeans RNSH
4
Food Service Systems
Cook Fresh
Cook Chill
Cook Freeze
Advantages and disadvantages
Types of equipment
NUTRIENT LOSSES
Nutrient losses
Natural vs Processed
Objectives
Understand the how different cooking
and preparation methods affect the
nutrient content of foods
•
•
•
•
•
•
Climate
Soil
Handling
Maturity
Feeding regimes
(for animals)
Genetic
•
•
•
•
•
•
•
•
Why process foods?
1. Raw foods are perishable. Processed to preserve,
pack or for storage (e.g. canned foods).
Preparation, milling
Heating
Drying
Chilling
Freezing
Irradiation
Packaging
Storage
6 processing principles that
preserve
1. Removing moisture (e.g. drying)
2. To produce a desired product (e.g. baked goods).
2. Treating with heat (e.g. pasteurisation, cook)
3. To prepare food for service.
3. Cold temperature (e.g. fridge, freezer)
Nutrients can be destroyed when food is processed
due to:
• Sensitivity to the pH of the solvent
• Oxygen
• Heat
• Light and/or any combination.
4. Acidity control
5. Chemical additives
6. Irradiation
5
Effects of Processing
Positive vs Negative
•
Anti-digestive factors
may be destroyed
•
Reduction of heat
sensitive vitamins
•
Increased starch
digestibility
•
Vitamins & minerals
leached
•
Bioavailability increased
•
•
Reduced microbial load
Reduced availability of
some minerals and amino
acids
•
Addition of antioxidants
Stability of nutrients
Karmas, E & Harris, RS. 1988, p4
Stability of nutrients
•
Vitamins
Vitamins A, B6, C, thiamin, riboflavin and folate
Vitamin C and folate most unstable
Losses of 20-60% (Moderately stable)
Vitamin A, B6, D, E, pantothenic acid
•
Minerals
Iron, zinc and calcium
Losses of < 20% (Stable)
Minerals, Amino Acids, Fatty Acids, Vitamins B12
and K
•
Dietary fibre
•
Losses of 60-100% (Unstable)
Vitamin C, folate, biotin, niacin, riboflavin, thiamin
•
•
Critical nutrients
Primary sources of nutrient
losses
Animal products
• Thaw drip
Plant products
• Trimming, slicing, soaking
•
Cooking drip
•
Leaching
•
Leaching
•
Heat losses
•
Cooking & holding losses
•
Storage
•
Reheating
Processing steps in large scale
food service
•
Purchasing
•
Chilling
•
Storage
•
Chilled storage
•
Preparation
•
Reheating
•
Cooking
•
Hot holding
•
Texture modification
6
Processing steps and losses
Purchasing (fresh*/frozen/canned*)
• Can occur with any type. Greater vitamin loss with canned,
although ‘fresh’ depends on storage time. (e.g. Spinach
can lose >50% Vitamin C if at 20°C for 2 days).
• Drying causes significant losses, especially as more water
is removed.
Storage
• Depends on the time, temperature* and the stability of
temperature.
• Frozen & canned products can continue to lose nutrients
(e.g. Vitamin C) in storage, but lower than the initial
processing losses.
Processing steps and losses
Preparation
• Thawing meat can result in significant vitamin losses,
especially if in water. Using the fridge or microwave is
best.
•
Trimming fruits and vegetables increases losses (e.g.
oxidation).
•
Soaking* also enhances losses (e.g. leaching). Aim to
soak or wash for a short time to minimise loss. (Current
trend is to utilise pre-prepared salads etc.)
*Significant loss is possible
Processing steps and losses
Processing steps and losses
Cooking** Most losses in this stage
• Boiling causes greater losses than steaming (Consider
water volume used).
• Grill & roasting have smaller losses than braising.
• Microwaving, stir frying & steaming seem similar when
using with minimal water.
• Baking/frying no significant leaching losses, but greater
vitamin destruction due to the high temperatures.
Chilling
Small losses if chilling is rapid (within 2hrs). Significant
losses if extended (6hrs)*. IHHC Guidelines recommend
within 1.5hrs for a gastronorm tray of food.
•
Chilled storage
• Vitamin C is most labile; has a linear loss with time.
Speculation about greater loss in long term cook chill, but
lack of 02 may influence.
• Overall, losses still lower in chilled storage, than with hot
holding.
Reheating
Smaller loss with individual microwaving.
Large scale food service, usually mass reheating.
Limited data, appears loss is greater when chilled food
heated in bulk, rather than individually- due to the time
involved?
There appears to be no significant differences in losses in
reheating, considering infrared, convection, conduction..
Processing steps and losses
Vitamin C loss in chilled storage
Hot holding**
• Significant losses. Even 30 minutes can cause losses.
•
Hot holding should be kept to <90 minutes.
Williams, PG. Journal of the American Dietetic Association 1996; 96(5): p492
7
Vitamin C and folate in cookcook-chill
and cook/hotcook/hot-hold systems
Williams, PG et al. 1995: p545
Vitamin C and folate in cookcook-chill
and cook/hotcook/hot-hold systems
•
After 1 day chilled storage, then reheating results in a
similar effect on Vitamin C to the following hot holding times;
• 91 minutes for Vitamin C
• 87 minutes for 5MeTHF
•
Plated and reheated after 3 days of being in chilled storage
would retain ~28% Vitamin C & 58% 5MeTHF.
•
In contrast, hot hold for 2hrs resulted in the retention of
~40.3% Vitamin C and 67.7% 5MeTHF.
•
If hot hold <90 minutes, vitamin retention is better in a cookserve than in a cook-chill system.
Williams, PG. 1994; p164
Williams, PG et al. 1995
Effects of processing in hospital
catering
• Vitamin C losses increase over the 5 days of storage.
• Losses increase with hot holding time. ‘Ideal’ 30 mins.
• Awareness of where losses occur, enables better planning.
Loss of Vitamin B6 in hot
holding
•
Riboflavin & niacin fairly stable
•
Thiamin usually less than 10% loss, for up to 2hrs
•
Vitamin C is lost rapidly
•
Vitamin B6 is lost
• Minimum loss of 10% after 1hr
• Up to 40% at 3hrs
Williams, PG, 1996
West, A et al. 1998; p285
Percentage losses after canning
Canned, Frozen and Fresh
Nutrient
Folacin
Asparagus 75.2
B1
66.7
B2
55
B3 B6
C
46.6 64 54.5
Carrot
58.8
66.7
60
33.3 80 75
Corn
72.5
80
58.3 47.1 0
58.3
Tomato
53.75
16.7
25
26.1
0
-
Karmas, E & Harris, RS. 1988: p344
8
Percent carotene retention in
stored canned foods
27°C
24
76
Temperature
Months
Apricots
10°C
12
96
10°C
24
94
18°C
24
90
27°C
24
56
95
91
Pineapple
100
83
78
53
75
64
63
Peaches
98
98
80
53
91
80
80
81
Asparagus (Gr)
97
93
91
86
94
75
75
74
Beans (Gr)
92
88
81
74
Temperature
Months
Apricots
10°C
12
94
10°C
24
91
Carrots
94
90
Peaches
95
Spinach
Tomatoes
Percent ascorbic acid retention
in stored canned foods
18°C
24
84
Karmas, E & Harris, RS. 1988: p345-347
Karmas, E & Harris, RS. 1988: p345-347
Vitamin C in fresh & frozen
vegetables
Peas
m
D
ay
37
A
D
ay
37
23
C
C
hi
lle
d
bi
en
t /C
hi
lle
d
Fr
oz
en
In
Fr
i ti
oz
al
en
12
m
on
th
s
d
hi
lle
bi
en
t
m
A
G
ar
de
n
Day 3-7 Chilled/Ambient
D
ay
Day 3-7 Chilled
bi
en
t
Chilled
Am
Day 2-3
37
Day 3-7 Ambient
D
ay
Ambient
fre
sh
Day 3
3
Garden fresh
35
30
25
20
15
10
5
0
D
ay
Day 0
mg/100g vitamin C present
Pea s
Peas, Broccoli, Green beans, Spinach, Carrots
Type and tim e of storage
Favell, DJ. Food Chemistry, 1998: p59-64
Broccoli
Spinach
Spina ch
25
20
15
10
5
D
ay
37
A
37
C
hi
lle
d
m
bi
en
t/C
hi
lle
d
Fr
oz
en
In
Fr
itia
oz
l
en
12
m
on
th
s
d
hi
lle
C
23
D
ay
A
m
bi
en
t
D
ay
37
D
ay
3
Am
bi
en
t
f re
sh
0
D
ay
mg/100g vitamin C present
m
A
Type and tim e of storage
30
G
ar
de
n
hi
lle
d
bi
en
t/ C
hi
lle
d
Fr
oz
en
In
Fr
itia
oz
l
en
12
m
on
th
s
d
D
ay
37
D
ay
37
C
C
hi
lle
m
bi
en
t
23
D
ay
D
ay
37
A
Am
bi
e
nt
fre
sh
3
D
ay
G
ar
de
n
mg/100g vitamin C present
Broccoli
90
80
70
60
50
40
30
20
10
0
Type a nd tim e of stora ge
9
Thiamin content of frozen steak
(mg/100g)
Initial
Constant
Temp (+ 1°C)
3.0
Fluctuating
Temp (+ 5°C)
3.0
-10°C
2.8
1.8
-20°C
2.9
2.1
-30°C
3.0
2.6
Karmas, E & Harris, RS. 1988: p561
Method of cooking broccoli vs
phenolic compound contents
•
•
•
•
•
Compared the influence of
cooking methods on phenols in
broccoli. 150g broccoli, 150ml
water
(A) High pressure
3 min
(B) Low pressure
5 min
(C) Steaming
3.5 min
(D) Microwaving
5 min
Microwave > Highest losses?
Overcooked
Steaming superior- short time & no
water contact
Vallejo, F et al. 2003: p1515
Karmas, E & Harris, RS. 1988, p308
Irradiation
•
Uses
•
•
•
•
Controls insects in spices, herbs, nuts &
grains
To reduce the level of bacteria in meat
Minimise sprouting in fruits & vegetables
Influence on nutrition
•
•
•
Similar vitamin losses to heat processing
No significant impact on carbohydrates,
protein and minerals
May increase fat oxidation
Further research required on
phytochemicals & antioxidants
Blanching & freezing on bioactive
compounds in vegetables
Effect of processing on major flavonoids
in onions
20-30% losses of antioxidant activity & total
phenolics
Significant (50%) reduction with peeling &
chopping
Up to 30% vitamin C lost with blanching
90% of quercetin (flavonoid) is in the 1st & 2nd
layers
Up to 50% folate lost
Fairly heat stable thereafter
Ewald, C et al. Food Chemistry, 1999: p231-235
Carotenoids & sterols stable
Puupponen-Pimia, R et al. Journal of the Science of Food and Agriculture, 2003:
p1389-1402
10
Recommendations to maximise
nutrient retention
In Summary
Dry Goods
Store dry goods at <20°C
Fresh goods
Minimise the time stored
Shop 2-3 times per week, if possible, to optimise
the retention of the nutrient value and appearance
Protect from heat and light
Stable refrigeration temperature
Always wash before use
Recommendations
Frozen foods
Keep freezer temperatures stable
Thaw in the refrigerator
Recommendations
Preparation
Cut foods just prior to service
Cooking
Cook larger vegetable portions
Restrict the time for ‘hot holding’
Use minimal water to cook vegetables
Consider steaming, microwaving and stir frying
References
Ewald, C, Fjelkner-Modig, S, Johansson, K, Sjöholm, I and Åkesson, B. Effect of processing
on major flavonoids in processed onions, green beans, and peas. Food Chemistry 1999;
64(2): p231-235
Favell, DJ. A comparison of the vitamin C content of fresh and frozen vegetables. Food
Chemistry 1998; 62(1): p59-64
Hunt, C. Vitamins in institutional feeding. Journal of Micronutrient Analysis 1990; 7:p193-206
Karmas, E & Harris, RS. Nutritional Evaluation of Food Processing (3rd edition). New York:
Van Nostrand Reinhold Company Inc; 1988.
Light N & Walker A . Cook-Chill Catering Technology and Management. Elsevier Applied
Science: Barking; 1990.
Mibey R & Williams P. Food service trends in New South Wales hospitals, 1993-2001. Food
Service Technology 2002; 2:95-103.
Puupponen-Pimiä, R, Häkkinen, S.T, Aarni, M, Suortti, T, Lampi, A.M, Eurola, M, Piironen,
V, Nuutila, A.M, Oksman-Caldentey, K.M. Blanching and long-term freezing affect various
bioactive compounds of vegetables in different ways. Journal of the Science of Food and
Agriculture 2003: 83(14): p1389-1402
Know where losses occur and plan accordingly
Include a variety of foods in your day that are
rich in critical nutrients
(e.g. fresh fruit for vitamin C, legumes and
green leafy vegetables for folate)
References
Vallejo, F, Tomas-Barberan, FA and Garcia-Viguera, C. Phenolic compound contents in
edible parts of broccoli inflorescences after domestic cooking. Journal of Food Science
Agriculture 2003; 30: p1511-1516
West, A, Walker, A and Lawson, J. The effects of food processing in hospital catering
systems. Conference Proceedings of ICCAS 98-Culinary Arts and Science II Global and
National Perspectives 1998: p283-289
Payne-Palacio J, Theis M. West & Wood’s Introduction to Foodservice (9th ed). Prentice
Hall; 2001.
Williams, PG. Vitamin retention in cook/chill and cook/hot-hold hospital foodservices.
Journal of the American Dietetic Association 1996; 96(5): p490-503
Williams, PG, Ross, H. and Brand-Miller, JC. Ascorbic acid and 5-methyl-tetrahydrofolate
losses in vegetables with cook/chill or cook/hot-hold foodservice systems. Journal of
Food Science 1995; 60:p541-546
Williams, PG. Food in Hospitals. PhD thesis. 1994
Puckett, RP. Food Service Manual for Health Care Institutions (3rd edition). San Francisco:
Jossey-Bass; 2004.
11