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TRANSCRIPT
Detection of food fraud and
adulteration using novel
spectroscopic techniques
Xiaonan Lu
Assistant Professor
Food Science, UBC
Date: Nov. 7th, 2016
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Food fraud incidents
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Oceana Survey of US Seafood:
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Food fraud incidents (con’t)
Figure 1. Food fraud incidents categorized by food group
(summarized by Food Protection and Defense Institute)
http://www.foodfraudresources.com/ema-incidents/ 4
Definition of food fraud• Food fraud
“the deliberate and intentional substitution,
addition, tampering, or misrepresentation of food,
food ingredients, or food packaging; or false or
misleading statements made for food products for
economic gain” – Spink and Moyer, 2011
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Definition of food fraud (Con’t)
Figure 2. Food protection risk matrix (Spink & Moyer, 2011)
Food
Quality
Food
Fraud1
Food
Safety
Food
Defense
Motivation
Gain: Economic
Harm:
Public Health,
Economic, or
Terror
Unintentional Action Intentional
1Includes the subcategory of economically motivated
adulteration and food counterfeiting
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Economic loss of all parties (i.e. food industry,
government, consumers)
Weaken consumers trust in food industry and
government
Potential health risks
allergens incorporated
pathogen contaminated
poisoning
Detriments of food fraud
Food safety
&
Food defense
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Traditional analytical techniques
• complex
• time consuming
Sample preparation
• complicated instrumentation
• marker specific methodology
LC/GC• complicated
instrumentation
• marker specific methodology
UV/DAD/MS
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Traditional techniques (con’t)
• Fail to achieve:
rapid analysis
high-throughput screening
user-friendly procedures
detection of new types of deceptive behaviors
• Alternative:
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Vibrational spectroscopies
• Raman and FT-IR spectroscopies
Vibrational signals of functional groups
Scattering or absorption spectra
Figure 3. Vibrational modes of molecules
symmetrical
stretching
Rocking Wagging TwistingFigure 4. Representative
Raman spectra
Asymmetrical
stretching
Scissoring
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Vibrational spectroscopies (con’t)
• NMR spectroscopy
Vibrational signals of nucleus
Resonance frequency spectra
NMR: nuclear magnetic resonance
Figure 5. Nucleic magnetic moment changes in
NMR spectroscopyFigure 6. Representative 1H
NMR spectrum
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Vibrational spectroscopies (con’t)
• Advantages
Non/less-destructive
Rapid
Comprehensive chemical composition
Unique fingerprinting features
Able to emerge any extraneous materials
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Current projects in the lab
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• Detection and quantification of beef and pork offal in
ground beef meat
Two types of
beef meat
Three types of
pork offal
Three types of
beef offal
Raman spectrometer
FT-IR spectrometer
Chemometric analyses
Figure 7. Schematic illustration of
experimental design 18
Figure 8. Differentiation of beef meat and offal pure samples by
PCA models. Left, representative PCA for Raman spectroscopy;
right, representative PCA for FT-IR spectroscopy (n=30)
PCA: principal component analysis19
• Detection and quantification of Sudan I in paprika
powder (Hu and Lu, 2016, Nature npj Science of Food, submitted)
paprika
powder
Sudan I
solution liquid extraction
centrifugation
rotor
evaporation
re-dissolve
Liquid-state
NMR tubesolid & liquid
mixture
HR MAS
solid-state
NMR rotor
supernatant
collection
HR MAS: high resolution magic angle spinning
Figure 10. Schematic illustration of experimental design
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y = 19122x + 28542R² = 0.9968
0.0E+00
2.0E+06
4.0E+06
6.0E+06
8.0E+06
1.0E+07
1.2E+07
0 200 400 600
Sp
ectr
a in
ten
sity a
t 8
.57
pp
m (
AU
)
Sudan I concentration in paprika powder (mg/kg)
Figure 11. Left, representative liquid-state 1H NMR spectra of Sudan I in paprika powder at
different concentrations (bottom to top: 20, 50, 100, 250 and 500 mg/kg); right, linear
regression of Sudan I concentration and NMR spectra intensity at 8.57 ppm (n=3)
Liquid-state 1H NMR
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y = 268.73x - 13248R² = 0.9885
0.0E+00
1.0E+05
2.0E+05
3.0E+05
4.0E+05
5.0E+05
6.0E+05
7.0E+05
0 500 1000 1500 2000 2500
HR MAS solid-state 1H NMR
Spectr
a inte
nsity a
t 7.8
9 p
pm
(A
U)
Sudan I concentration in paprika powder (mg/kg)
Figure 12. Left, representative HR MAS solid-state 1H NMR spectra of Sudan I in paprika
powder at different concentrations (bottom to top: 225, 675, 1350, 1800 and 2250 mg/kg);
left, linear regression of Sudan I concentration and NMR spectra intensity at 7.89 ppm (n=3)
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Next step…
Comparison and integration of
chemical library (UBC) &
molecular library (Guelph)
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BOLD Systems
Web-Accessible Data and
DNA Barcodes
Specimen Collection Data
Tissue Sample Photograph
PCR Amplify SequenceExtract DNA
The DNA Barcoding Workflow – Library Building
Courtesy by Bob Hanner (University of Guelph) 24
Acknowledgement• Lu Food Safety Engineering Lab
• Yaxi Hu
• Prof. Eunice Li-Chan
• Dean Rickey Yada
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