Analytical Techniques in Food Authentication Yat Yun Wei Food Safety Division Health Sciences Authority 1
Outline of presentation What is Authentic Food? Why is there a need for reliable techniques for Food authentication? Analytical techniques - Chromatography - Spectroscopy - DNA and proteomics - Stable Isotopes Conclusion 2
What is Authentic Food? When is food not authentic? Economically Motivated Adulteration False Declaration of Geographical Origin False declaration of Farming Regime / production system 3
Food Authenticity Issues 1) Economically Motivated Adulteration (EMA) the fraudulent, intentional substitution or addition of substance in a product for the purpose of increasing the apparent value of the product or reducing the cost of its production --- FDA Open Meeting on Economically Motivated Adulteration (2009) a) Addition of non-permitted substances to meet or enhance specifications b) Addition or Substitution of ingredients with lower-valued ones Melamine in milk Cheap Sugars in honey Premium rice with cheaper alternatives 4
Food Authenticity Issues 2) False declaration of geographical origin e.g. Labeling South American beef as British beef [1] European Commission established rules for associating food and agricultural products with a geographical location. Aim: To protect interests of both producers and consumers PDO PGI TSG [1] Heaton, K.; Kelly, S. et al. Food Chemistry (2008), 107, p506-515 5
Food Authenticity Issues 3) False declaration of farming regime / production systems - Conventional Food labeled as Organic - Farmed fish labeled as wild fish - Non-corn-fed chicken labeled as corn-fed chicken [2] [2] http://www.trace.eu.org/ws/york/katharina_heinrich.pdf 6
Problems arising from Food Authenticity Issues Reduced Confidence of consumers Health Concerns Difficulty in sale of Authentic products Need for reliable authentication techniques! 7
Top 5 analytical techniques for food authentication 1. HPLC 2. IR spectroscopy 3. GC 4. IRMS 5. Hyphenated MS Adulteration Geographical origin Farming regime Species Differentiation 7. PCR 9. ELISA Moore, J.C., Spink, J., Lipp, M. Journal of Food Science (2012), 77,pp R118-R126 8
Chromatographic techniques Detection of adulteration of targeted substances - melamine in milk by HPLC - Sudan dyes in egg yolk by HPLC Confirmation with a mass spectrometric method Detection of partial / total substitution with cheaper, similar alternatives by profile of specific classes of compounds or by detection of specific markers - Authenticity of fruit juices by LC profiling of polyphenols [3] - Authenticity of olive oil by GC profiling of fatty acids [4] [3] Nollet, L. Food Authentication by HPLC, Sept 2004. [4] Tsimidou, M.; Macrae, R.; Wilson, I. Food Chemistry (1987), 25, pp251-258. 9
Example: Authenticity of fruit juices by HPLC Different fruits have their own characteristic phenolic compounds: Grapefruit Juice Orange Juice Nollet, L. Food Authentication by HPLC, Sept 2004. 10
Spectroscopic techniques -IR Not specific analytes, but food composition as a whole Comparison of the food in question with a known Fingerprint Used in combination with chemometrics tools - Detection of adulteration of olive oil, honey [5] - Geographical Origin of olive oil [6] [5] http://www.teagasc.ie/research/reports/foodprocessing/4907/eopr-4907.pdf [6] Tapp, H.S., Kemsley, E.K., et al. Journal of Agricultural and Food Chemistry (2003) 51, 6110-6115 11
Example: Geographical Origin of olive oil by FT-IR 100% success rate achieved from 8 variates Greece Italy Portugal Spain Tapp, H.S., Kemsley, E.K., et al. J. Agric. Food Chem. (2003) 51, 6110-6115 12
DNA and proteomics-based techniques Species Differentiation - Differences in DNA sequence, or protein and peptide markers allows differentiation between different animal or plant species Source: TODAYonline, 7 Nov 2012 13
Stable Isotopic Techniques Some facts about stable isotopes Stable vs unstable isotopes Unstable isotopes are also known as radioisotopes. They have unstable nuclei and give off an extra neutron to attain stability (radioactive decay) Stable isotopes do not decay Example 14 C and 13 C are both isotopes of Carbon but 13 C is stable while 14 C is radioactive. 14
Common Stable Isotopes and their % composition S Source: Meier-Augenstein W. (2010) Stable Isotope Forensics. 15
How are Stable Isotopes useful to us? The distribution of isotopes is not the same throughout the earth and among different organisms This unbalanced distribution is known as fractionation of isotopes. The fractionation of isotopes gives rise to distinct isotopic signatures in plants and animals which is useful in the differentiation between botanical and geographical origins and farming regimes 16
Stable Isotope Analysis by Isotope Ratio Mass Spectrometry (IRMS) 13 C/ 12 C 15 N/ 14 N 18 O/ 16 O 2 H/ 1 H 34 S/ 32 S 17
Useful Applications of Stable Isotopes in Food Authentication Botanical Origin Geographical Origin Farming Regime / Production System 18
Useful Applications of Stable Isotopes in Food Authentication Botanical Origin Geographical Origin Farming Regime / Production System 19
Botanical Origin Difference in photosynthetic pathways results in different Carbon isotopic ratios C 3 plants C 4 plants Absorbs 13 C more slowly than 12 C Less enriched in 13 C Lower 13 C/ 12 C ratios Wheat, oranges, flowering plants Absorbs 13 C more quickly than 12 C More enriched in 13 C Higher 13 C/ 12 C ratios Cane, maize 20
Application: Adulteration of honey Authentic honey has the carbon isotopic signature characteristic of a C 3 plant. Adulteration in the form of cheaper sugars, such as cane and corn sugars (C 4 ) Harms the honey industry and damages consumer confidence. AOAC Official Method 998.12 C 4 plant sugars in honey C Isotopic ratios of bulk honey and extracted protein are % C-4 sugars > 7% analyzed Adulteration!! C 4 sugars shift the Carbon isotopic ratio of honey but not the protein 21
N Isotopes Soil Nutrition H and O Isotopes Precipitation and groundwater Geographical Origin C Isotopes Diet (C3 or C4) Elemental Profile Soil composition Stable Isotope Analysis is often used hand-in-hand with Elemental Analysis, Data is further subjected to multivariate statistical analysis 22
Application: Geographical Origin of rice Joint collaboration between HSA and FERA,UK. 226 samples of rice, 15 different countries Objective is to classify the different rice samples into their respective regions by Canonical Discriminant Analysis (CDA) C, N, H, O Stable Isotopes (IRMS) + Multiple elements (ICPMS) Li, A. Separation Science Asia, June 2012. Food Safety through provenancing of the food we eat 23
Rice Classification by CDA Further Classification India & Pakistan Southeast Asia Li, A. Separation Science Asia, June 2012. Food Safety through provenancing of the food we eat 24
Further Classification by CDA Analytes selected for CDA include: δ 13 C, δ 15 N, δ 18 O, Mg, Al, K, Mn, Fe, Co, Cu, Zn, Se, Mo, Cd Li, A. Separation Science Asia, June 2012. Food Safety through provenancing of the food we eat 25
Synthetic fertilizer or organic manure? Caged or freerange chicken? Wheat-based or maize-based diet? Farming Regimes Wild fish or farmed fish? Organic or conventional? 26
Application: Determination of farming regime of fish Wild or Farmed? Wild Cod shows higher 15 N/ 14 N and 13 C/ 12 C ratios than farmed cod Due to a difference in diet Bay, L.; Chan J.S.H.; Walzyck, T. 19 th International Mass Spectrometry Conference (2012) 27
Conclusion A multi-disciplinary approach is often necessary to solve the authentication problem. 28
The End 29