LIN/COPPE/UFRJ
ELECTRON SPIN RESSONANCE
IDENTIFICATION OF IRRADIATED FOOD
Prof. Edgar Francisco Oliveira de Jesus*
Prof. Ricardo Tadeu Lopes*
Dr. Alexandre Malta Rossi**
*Laboratório de Instrumentação Nuclear (Escola de Engenharia/COPPE/UFRJ)
**Centro Brasileiro de Pesquisas Físicas (CBPF)
LIN/COPPE/UFRJ
Standard
Method
EN 1784
GC of hydrocarbons
EN 1785
GC/MS of 2-alkylcyclobutanones
EN 1786
EN 1787
ESR spectrocopy of bones
ESR spectrocopy of celulose
EN1788
pr EN 13708
Thermoluninescence of silicate
ESR spectrocopy of sugars
pr EN 13751
pr EN 13783
pr EN 13784
Photostimulated luminescence
Microbiological screening
DNA comet assay
Products
Chicken, Pork, Beef,
Avocados, Mangoes, Papayas,
Camembert
Chicken, Pork, Liquid whole
egg
Chiken, Fish, Frog legs
Paprika powder, Pistacho nut
shells, Strawberries
Herbs and Spices, Shrimps,
Dried Papayas, dreied
mangoes, dried figs Raisins
Herbs and Spices, Shellfish
Herbs and Spices
Chiken, Pork, Plant cells,
seeds.
H. Delincée - “Analytical methods to identify irradiated food¯¯a review”
Radiation Physics Chemistry; 63, 3-6; p.455-458, 2002
LIN/COPPE/UFRJ
Electron Spin Resonance (ESR)
LIN/COPPE/UFRJ
Radiation Sources
 “Brokhawen Portable Cesium Development Irradiator”
(BPCDI) - IPE, CETEX., Guaratiba, RJ.
Césio-137 with 3,99 x 1015 Bq (108.000 Ci), in 1969
Actual dose rate - 30.0 Gy/min
 Gammacell 220 Excel - Nordion - Laboratório de
Instrumentação Nuclear COPPE/UFRJ
Cobalto-60 with 3.08 x 106 Bq (12,000 Ci), in 2000
Actual dose rate - 90 Gy/min
LIN/COPPE/UFRJ
IPD Irradiator - Frontal view.
LIN/COPPE/UFRJ
Gammacell Irradiator
LIN/COPPE/UFRJ
ESR Measurements
 Bruker ESP300E spectrometer (CBPF)
 Bruker EMS104 spectrometer (LIN)
LIN/COPPE/UFRJ
Alcoholic Extraction Treatment
 Compact the pulp without seeds and skin, in a uniform sample;
 About six grams of the pulp is treated with 40 ml 80% ethyl
alcohol solution in de-ionized water;
 The insoluble solid fraction is then separated by filtration;
 Remove the excess of water and left to dry at ambient
temperature for one hour;
 100 mg of the dry matter is then pressed in an acrylic matrix by
a steel stick;
 The resulting sample, consisting of a cylinder 2.5 mm in
diameter and 15 mm high, is measured by ESR in a quartz tube.
LIN/COPPE/UFRJ
Products
 Papaya
Apple
Pear
Tomato
Pineapple
Mango
Kiwi
Strawberry
 Pumpkin
Carrot
Potatoes
 Onions
Garlic
LIN/COPPE/UFRJ
ESR Spectra
3.05 mT
g = 2.0045
g = 2.0201
g = 2.0030
g = 2.1985
Tomato
Papaya
0.6 mT
0.6 mT
kiwi
1.0 mT
342
344
346
348
350
Magnetic Field (mT)
Irradiated Samples
352
354
342
344
346
348
350
352
Magnetic Field (mT)
Non-irradiated Samples
354
LIN/COPPE/UFRJ
ESR Signal Intensity Variation with Dose
Apple
g = 2.0202
g = 1.9852
5.0 kGy
4.0 kGy
3.0 kGy
2.0 kGy
1.0 kGy
340
342
344
346
Magnetic Field (mT)
348
350
352
LIN/COPPE/UFRJ
ESR Spectra of tomato irradiated with additive doses
1200 Gy
950 Gy
700 Gy
450 Gy
200 Gy
2 mT
Magnetic Field
LIN/COPPE/UFRJ
ESR Sensitivity for Different Products
(Intensity/Gy)
Kiwi
Papaya
Tomato
Strawberry
Apple
Pineapple
Pumpkin
Carrot
5.49  0.08
4.97  0.19
4.22  0.22
1.92  0.23
2.40  0.34
3.75  0.37
1.22  0.16
2.28  0.28
MDDose (Gy) * Cellulose (g/100g)
94
104
112
384
238
146
396
222
0.94
0.72
0.49
0.48
0.56
0.60
0.47
0.54
* Calculated as the dose necessary to introduce a signal twice the background
intensity for non-irradiated samples.
LIN/COPPE/UFRJ
Dose Determination - Additive doses
ESR Intensity (au)
9000
ESR Intensity (au)
6000
Pineapple irradiate with 0.5 Gy
Carrot irradiate with 0.5 Gy
8000
5000
7000
6000
4000
5000
3000
4000
3000
Linear Regression
D = 0.56 Gy
o
2000
Y = 1638.54 + 2913.58 * X
1000
1000
0
-1.0
Linear Regression
2000
Y = 929.99 + 1896.74 * X
D0 = 0.49 Gy
r = 0.9911
r = 0.998
-0.5
0.0
0.5
1.0
Dose (Gy)
1.5
2.0
2.5
0
-1.0
-0.5
0.0
0.5
1.0
Dose (Gy)
1.5
2.0
2.5
LIN/COPPE/UFRJ
ESR Intensity Decay
3500
7000
6000
Carrot
Strawberry
3000
ESR Intensity (au)
ESR Intensity (au)
5000
2500
2000
4000
3000
2000
1000
1500
0
0
2
4
6
Weeks
8
10
12
0
10
20
Days
30
40
50
LIN/COPPE/UFRJ
10000
8000
ESR Intensity (au)
300 Gy
6000
200 Gy
4000
150 Gy
2000
100 Gy
0
NI
-2000
0
200
400
600
Chanel
Onions
800
1000
1200
LIN/COPPE/UFRJ
10000
8000
Y Axis Title
6000
4000
2000
0
-2000
342
344
346
348
Magnetic Field (mT)
Garlic
350
352
354
LIN/COPPE/UFRJ
Food Irradiation Research
EMBRAPA
 Fruits and other vegetal products
FACULDADE DE MEDICINA VETERINÁRIA - UFF
 Frog legs;
 oyster;
 mussel;
 crab;
LIN/COPPE/UFRJ
Food Irradiation Research
FACULDADE DE MEDICINA VETERINÁRIA - Nova Iguaçu
 Chicken;
 Sausage;
 Beef;
 Cheese.