Methods
The objective was to prepare a dish for potluck 1 and to calculate or otherwise determine the energy (Kj),
contaminant burden, and basic nutritional information for dish 1 and to bring a lower energy and lower
contaminant burden dish (dish 2) for potluck 2. The energy associated with the production,
transportation, storage, packaging, and preparation were calculated following a series of assumptions.
Due to the size and diversity of the food industry it was not possible to learn everything about a specific
food item. The assumptions provided a framework and put logistical limitations on the information. One
of the concepts included in the assumptions was that of “free energy.” Energy and therefore a good was
considered “free” if it did not require manufactured energy inputs for production such as wild meat, fish,
water, and home-grow organic goods. It was also assumed that human energy inputs such as manual
labour, walking, and bicycling were free. Energy was calculated to be as specific for a food item as
possible, that is the energy to transport and store the item were proportioned for its weight and size. This
required the assumption that items were only shipped when a transport was loaded to its maximum gross
vehicle weight or gross tonnage.
The energy and contaminant information were collected using many different sources. Food
manufactures, suppliers, and growers were contacted and questioned regarding their energy use for
growing or making a specific food item. Suppliers, such as grocery stores, were used to identify where
the food product originated. Transportation companies were questioned to identify which routes were
used and the quantities and types of fuels consumed. Literature searches were used to identify the
contaminate loading of food items. Online Canadian and International food health information was
consulted, along with scientific articles, and industry information. Direct analytical information was also
used, samples from three select ingredients from November were analysed for total metals (cadmium,
copper, iron, lead, and zinc) using an atomic absorption spectrophotometer in Leah Bendell-Young
laboratory at SFU. All of the contaminant and energy information was tabulated and is presented in the
following article.
Assumptions:
The assumptions for all potluck dinners were grouped and separated into seven
categories. Where assumptions are specific for a food item the item is given otherwise
the assumptions were applied to more than one food item in multiple dishes.
Free Energy and Free Goods
•
•
•
•
•
Energy to transport potluck dishes to Simon Fraser University for the potlucks
was not included in the total energy consumption of the dish;
Manual Labour to produce, process, package food items, and cook the dish was
not included in the total energy of the dish;
Walking, and bicycling was considered free;
The sun’s energy used to produce crops was not included;
Wild meat, fish, and organic home-grown products were considered a free good
Production and Processing of Food Items
Production and processing energy was included in the total energy of the dish,
Energy input from fertilizer over 65,000 acres is equal to 4.76 x 106 gallons of
gasoline. 1 gallon of gasoline equals 1.30 x 108 Joules;
• The energy inputs in New York apple production are comparable to those for
apple production in the Okanagan;
• The inputs for winter wheat in New York are comparable to those for
Saskatchewan;
• Energy requirements for flour production at a mill in Denmark are equal to those
for flour production at a Roger’s Flour mill in Armstrong BC;
• Energy used in Sweet Potato production in California is considered negligibly
different from those grown in Brazil;
• The extractor used in honey production has a power rating of 350 W, was used for
20 minutes to produce 101.2 kg of honey;
• A gas blower was used for the honey frames to be taken off-site, for honey
extraction and required 764.4 W;
•
•
Dairy
8000 to 16000 MJ/ha for animal production
Whole milk production is 3.34 MJ/kg for conventional farms
• The cow was capable of milking and no energy inputs were needed to grow the
cow before it could milk.
•
•
Packaging and Storage Costs
•
•
Generally packaging costs for individual food items was not included
Wooden and cardboard boxes and crates used in packaging were recycled,
therefore no energy was associated with packaging;
•
•
•
•
Storage (including refrigeration/freezer) cost were included and were pro-rated
per space used in the freezer/refrigerator for the size of the food
Fruit purchased the day of delivery so no refrigeration was necessary.
Butter was stored at the market in a refrigerated food display for approximately
14 days.
Energy used in the packaging of cheese was adopted from Pimentel 1996 which
offered an energy use of 559kcal for a small polyethylene pouch.
Cooking Costs
•
All cooking energy costs by electrical/gas appliances were included
Travel
Travel costs included all fuel consumption by truck, boat, or plane to get the raw food
item to processing and distribution centres and then to market as well as trips to the
grocery stores by potluck participants;
• Fuel efficiency of a transport truck: 0.395 L/Km
• Fuel efficiency of car:0.08L/Km
• Fuel efficiency of an SUV:0.12L/Km
• Energy conversion for diesel: 146488 BTU/US-gal
• Energy conversion for gas: 125000 BTU/US-gal
• Where exact rout information was unknown MapQuest® was used to identify
route distances and travel was restricted to Canada (even if it was shorter to travel
through the United States)
• For apple crumble, machinery, fuels, and seeds, travelled an average distance of
1000 Km’s
• Queen of Prince Rupert gross tonnage 5970618 kg
• Queen of Cowichan gross tonnage 6670292 kg.
• Transportation energy inputs were calculated assuming all transport was done by
truck, with a value of 1.2 kcal/kg/km (Pimentel and Pimentel, 1996)
• Milk used to make the cheese travelled from a farm within an average distance of
100km to Vaughan and then 30 km from Vaughan to Toronto and then 4511 km
to Vancouver.
Contamination
•
•
•
Health Canada’s Guide of Pesticide Residues and trace element concentrations are
representative of approximate values for the ingredients use;
Contaminant burden for organic sweet potatoes (not including the peel) is equal to
the contaminants found in the soil.
Crabs store most lipophilic contaminants in the hepatopancreas and since it is the
muscle that was eaten these contaminants are considered negligible.
•
•
•
•
•
Garden vegetables do not exceed the allowable levels of organic and inorganic
contaminants for non-contaminated soils.
Contaminant levels in the moose not considered health risk because it is low on
the food chain and therefore avoids biomagnification. Also they are lean animals,
therefore contaminants which are lipid-soluble are low in moose. Cadmium is the
only contaminant which is at a slightly higher level – but is concentrated in the
kidneys and liver, not in muscle tissue.
Contaminants found in Lemon Juice approximate the contaminants found in
whole lemons including the rind.
A study completed on Alaskan Halibut found fish to be relative clean of
contaminants. Pacific Halibut caught near the Queen Charloette Islands was
similar to Alaskan Halibut;
Butter contaminants are similar to cheese.
Equations:
The following standard equations were used to calculate energy specific to each food
item.
Energy in diesel.
& 1US ' gal # & 146488 BTU
TotalEnergy (kj ) = (LitersDiesel (L ))x$
! x$$
% 3.7854118 L " % 1US ' gal
# & 1.05505585kj #
!! x$
!
1BTU
"
" %
Energy in gasoline.
& 1US ' gal # & 125000 BTU
TotalEnergy (kj ) = (LitersGas (L ))x$
! x$$
% 3.7854118 L " % 1US ' gal
# & 1.05505585kj #
!! x$
!
1BTU
"
" %
Energy per food item.
FoodItemEnergy (kj ) =
TotalEnergy (kj )
xFoodItemWeight (kg )
GrossVehicleWeight (kg )
Energy Levels - Potluck 1
Ingredient
Quantity
(unit)
(MJ = a megajoule or one million units of energy)
Production
(MJ)
Processing
(MJ)
Packaging
(MJ)
Transport by
Transport by
Refrigeration (MJ)
Transport Truck (MJ) Personal Vehicle (MJ)
Preparation/
Cooking (MJ)
Total MJ
Required
Apple Crumble
Apples
10 cups
0.69
0.51
1.20
Oats
1.3 cups
3.53
ip
0.78
0.38
4.69
Sugar
2 cups
12.9
ip
1.15
0.25
14.3
Butter
1.3 cups
16.0
ip
0.76
0.01
16.8
1.21
Flour
1.3 cups
0.11
0.15
1.47
Cinnamon
2 tsp.
0.01
0.01
Total
34.3
0.11
2.69
1.30
0.23
555
22
615
Greek Salad
Red Onion
148 g
0.07
0.80
0.00
0.87
Green Pepper
328 g
0.46
3.20
0.01
3.67
Red Pepper
328 g
0.46
3.20
0.01
3.67
Tomatoe
600 g
0.12
1.69
0.19
2.00
Cucumber
600 g
0.82
0.186
0.01
1.02
Olives
454 g
0.43
1.58
1.62
3.64
Olive Oil
125 ml
0.14
2.26
2.11
0.54
5.06
Feta Cheese
200 g
7.26
0.13
0.27
0.21
7.88
Total
9.76
2.40
13.04
2.60
0
0
0
27.8
Bread, Brie and Roasted Garlic
Brie
1 kg
61.6
14.2
2.34
10.9
88.9
Bread
10 loaves
0.16
0.03
3.78
3.97
Flour
2 kg
3.48
0.41
1.86
5.74
Sugar
50 g
0.02
0.12
0.01
0.05
0.20
Salt
50 g
0.12
0.01
0.11
0.23
vegetable Oil
200 ml
0.54
0.47
0.05
0.74
1.80
Yeast
70 g
0.17
0.04
0.15
0.36
Garlic
4 Cloves
0.08
1.15
7.2
8.43
Total
65.9
15.3
2.60
14.9
0
0
10.98
110
Vegetarian Curry
Butter
4 tbsp
0.5000
0.1453
0.8322
1.48
Potatoes
910 g
0.0068
0.0243
0.03
Brocolli
454 g
0.0064
0.3710
0.38
Bell Pepper
454 g
0.0003
0.0008
0.0121
0.01
Onion
110 g
0.0028
0.0407
0.04
Coconut Milk
40 g
0.0030
2.1690
2.17
Garlic
24 g
0.0020
0.0955
0.10
Curry/Corriander/Etc. 4 tsp
0.1241
0.2007
0.32
Pepper
2.1 g
0.0049
0.1550
0.16
Salt
1.8 g
0.9300
0.0662
1.00
Tofu
1 lb
0.9436
1.8607
1.3547
4.16
Total
1.59
2.94
5.32
14.4
24.3
Grilled Halibut
Halibut
70.13
Lemon
0.30
Salt
0.18
Dill
0.15
Total
70.76
* Refrigeration includes both commercial and home refrigeration
** Items were not considered to be organic (pesticides, fungicides, ect. were used for wheat and apples)
***Energy inputs are what was needed for the total amount of ingredient used in the dish
Contaminant Levels 1stPotluck
Contaminant
Dish
Apple Crumble
Apples
Oats
Sugar
Butter
Flour
Cinnamon
Total
Quantity
(unit)
10 cups
1.3 cups
2 cups
1.3 cups
1.3 cups
2 tsp.
Metals (!g)
Organic Contaminants (!g)
Al
As
Cd
Cu
Hg
Mo
Pb
Zn
PCBs
Dioxins
Total Pesticides
-
-
-
-
0.17
0.17
-
15.30
4.00
6.05
7.79
33.14
2448.00
40.00
90.80
4720.00
7299
1.31
1.31
1.70
1.70
29744.00
251.00
29995
0.08
1.29
1.29
0.02
1.80
1.11
5.59
-
0.01
0.02
0.02
0.01
0.02
0.08
0.41
0.83
0.83
0.57
0.04
0.89
3.56
-
-
0.00
0.04
0.04
0.00
0.00
0.03
0.11
1.41
1.13
1.13
1.20
0.20
73.66
78.74
NA
0.81
0.81
NA
0.00424 TEQ
0.004
20.89
144.87
144.87
6.22
12.43
0.00
0.00
0.00
329.28
-
0.03
0.03
0.00
0.00
0.04
0.04
0.02
0.02
-
0.25
0.25
0.00
460.00
460.00
-
426.00
360.00
786.00
341
284158
975
586
8.71
286069
-
0.91
36.31
3.81
8.01
1.30
50
3.27
812.54
220.85
376.59
44.55
1458
0
3.32
44.64
31.69
9.96
1.32
91
0.84
6.29
4.84
16.19
0.22
28
34.65
2640.36
1671.58
514.45
155.36
5016
50.50
51
0.0001
0.0001
0.11
3450
764.32
981.47
6222
48.00
240.00
1072
126000
5000
42560
186338
0.00
36.8
36.80
0.00
920
920.00
0.00
0.00
184
184.00
920
920.00
0.00
0.00
0.00
#
#
#
#
#
#
Greek Salad
Red Onion
148 g
Green Pepper
328 g
Red Pepper
328 g
Tomatoe
600 g
Cucumber
600 g
Olives
454 g
Olive Oil
125 ml
Feta Cheese
200 g
Total
Bread, Brie and Roasted Garlic
Brie
1 kg
Bread
10 loaves
Flour
2 kg
Sugar
50 g
Salt
50 g
Vegetable Oil
200 ml
Yeast
70 g
Garlic
4 Cloves
Total
Vegetarian Curry
Butter
4 tbsp
Potatoes
910 g
Brocolli
454 g
Bell Pepper
454 g
Onion
110 g
Coconut Milk
40 g
Garlic
24 g
Curry/Corriander/Etc.4 tsp
Pepper
2.1 g
Salt
1.8 g
Tofu
1 lb
Total
Grilled Halibut
Halibut
2.87 kg
Lemon
184 g
Salt
31 g
Dill
4.0 g
Total
Potluck 1 Summary Table
Dish
Total Energy
Consumed (MJ)
Apple Crumble
615
Greek Salad
27.8
Bread, Brie and Roasted Garlic
110
Vegetarian Curry
24.3
Grilled Halibut
70.76
MJ = 1 megajoule of energy or one million units of energy..
Major Contaminants
Pesticides on Apples, Dioxin/Furans and PCBs in Butter
Pesticides on Bell Peppers, Dioxin/Furans and PCBs in
Cheese
Primary concern PCBs from Cheese
Pesticide residues on vegetables, PCBs and Dioxins in
butter
none
Energy Levels Potluck 2
MJ= Megajoule
(one million units of energy)
Ingredient
Crab Cakes
Dungeness Crab
Organic Sweet Potatoes
Total
Sushi
Organic Mangoes
Homegrown Chives
Organic Avocados
Organic Carrots
Organic Cucumbers
Nori Sheets
Organic Horseradish
Organic Apples
Total
Fruit Salad
Honey
Yogurt
Apples
Apple-pears
Kiwi
Total
Mashed Potatoes
Potatoes
Honey
Garlic
Rosemary
Chilli peppers
Total
Moose Stew
Moose
Water
Potato
Onion
Squash
Garlic
Chilli Pepper Seeds
Rosemary
Lemon Verbena
Bay Leaf
Total
Transport by
Transport by
Personal
Refrigeration
Truck (MJ) Vehicle (MJ)
(MJ)
Quantity
(unit)
Production
(MJ)
Processing
(MJ)
Packaging
(MJ)
Preparation/
Cooking (MJ)
Total MJ
Required
550 g
2055 g
-
0.239
0.239
0.000
0.000
0.107
0.107
0.011
0.011
14.597
4.140
0.011
0.346
19.095
250 g
5g
250 g
200 g
250 g
5.00
100 g
328 g
-
1.719
0.160
0.110
1.300
1.840
1.960
0.138
7.227
0.000
0.646
2.800
0.350
0.890
2.740
0.735
3.180
11.341
14.200
1.400
0.008
0.022
0.129
0.213
0.054
16.026
0.103
0.103
0.000
0.000
16.565
0.103
4.360
0.468
2.212
4.709
2.908
3.372
34.697
63g
1000 g
1250 g
1250 g
1000 g
-
0.003
2.074
2.077
0.001
1.027
1.028
0.270
2.865
3.135
0.009
0.329
0.338
0.103
0.103
28.033
28.033
0.000
0.282
34.431
34.713
1815 g
160 g
100 g
3 tbsp
20 g
0.003
0.003
0.001
0.001
0.270
0.270
0.047
0.120
0.167
0.000
0.000
7.000
0.047
0.394
7.441
1130 g
310.5 g
1200 g
150 g
200 g
20 g
3g
3g
3g
3g
-
0.000
0.000
0.000
0.000
3.200
0.075
0.0003
0.0002
3.275
1866.910
1866.910
4.320
1870.110
0.075
0.0003
0.0002
1874.505
Contaminant Levels 2nd Potluck
Contaminant
Dish
Crab Cakes
Dungeness Crab
Organic Sweet Potatoes
Total
Sushi
Organic Mangoes
Organic Avocados
Organic Carrots
Organic Cucumbers
Nori Sheets
Organic Mangoes
Homegrown Chives
Organic Horseradish
Organic Apples
Total
Fruit Salad
Honey
Yogurt
Apples
Apple-pears
Kiwi
Total
Mashed Potatoes
Potatoes
Honey
Garlic
Rosemary
Chilli peppers
Total
Moose Stew
Moose
Water
Potato
Onion
Squash
Garlic
Chilli Pepper Seeds
Rosemary
Lemon Verbena
Bay Leaf
Total
Metals (mg)
Hg
Pd
Cr
Al
As
Cd
Cu
0.0
0.0
0.012
0.026
0.038
2.624
2.624
0.059
0.059
0.001
0.316
19.490
0.414
20.221
0.0
0.038
0.009
0.003
0.050
0.752
0.000
0.679
0.003
1.080
2.514
0.0
0.0
0.043
0.043
0.075
0.084
0.637
0.796
0.0
0.020
0.020
0.002
0.002
0.100
0.100
0.0
0.0
0.008
0.008
0.0
0.0
0.002
0.002
0.0
0.0
0.0
0.0
0.0
0.0008 0.0009
0.0031 0.0016 0.400 0.0006
0.0024 0.490 0.960 0.0012
0.150 0.150 4.500 0.015
0.089
0.015
0.0006 0.003 0.090 0.0003
0.0006 0.003 0.090 0.0003
0.0006 0.003 0.090 0.0003
0.0006 0.003 0.090 0.0003
0.158 0.758 6.221 0.019
Organic Contaminants (mg)
PCBs Dioxins
Pesticides
Mo
Zn
Mn
Pb
0.0
0.023
3.078
3.101
0.094
0.094
0.0
0.0
0.0
0.0
0.750 3.894
0.000
3.320 4.190
11.860 2.170
0.703 0.949
16.633 11.203
0.014
0.020
0.003
0.037
0.0
0.0
Kumulus 80DF, Dipel 2X (unknown
0.0
2.000
2.000
0.020
0.020
0.002
0.002
-
-
trace
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.002
0.002
0.0
0.0
trace
0.0
0.031
0.031
0.0
0.048
7.5
0.150
0.150
0.150
0.150
8.148
3.104
0.015
0.0003
0.0003
0.0003
0.0003
3.120
0.0
0.015
0.0003
0.0003
0.0003
0.0003
0.016
0.012 0.011
0.012 0.011
32.000 100.9
1.550 0.015
5.200
12.000
0.870
0.150
0.240
0.240
0.240
0.240
52.730 100.915
amts)
Potluck 2 Summary Table
Dish
Total Energy
Consumed (MJ)
Major Contaminants
Difference In Total Energy
Consumed From Potluck 1
Crab Cakes
19.095
Crab Muscle: Cd, Cu,
Hg, Zn, Mn; Sweet
potatoes: Cd, Zn, Cr
188%
vs
Apple Crumble
Sushi
34.697
Vegetables: Al, Cd, Cu,
Mn, Mo, Pb
-22.1%
vs
Greek Salad
Fruit Salad
34.713
Honey: Cd, Pb; Yogurt:
As, Cu, Cr, Zn
104%
vs
Bread, Brie and Roasted Garlic
Mashed Potatoes
7.441
Honey: Cd, Pb
106%
vs
Vegetarian Curry
Moose Stew
1874.505
Stew: Zn, Pb, Mg, Cu &
Water: PCBs
-185%
vs
Grilled Halibut
MJ = 1 megajoule or one million units of energy.