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Feasibility study for using rapid and automated spectral imaging for food authenticity testing - FA0136

Authenticity of pasta and basmati rice samples is currently determined using molecular biology techniques focussing on DNA as a target analyte. Whilst proven to be relatively effective, these approaches are destructive, take time and expertise, require access to expensive laboratory equipment, and issues have arisen regarding the ability to quantitate the level of adulteration and take into account new varieties.
There is therefore a need for an alternative or additional complimentary approach to be used in terms of verifying food authenticity and grain/seed types, that will add value to the pre-existing molecular methods and over come some of the inherent difficulties that are encountered when implementing these relatively expensive and time consuming techniques.
Recent advances in the field of spectral imaging have facilitated the development of laboratory instruments that use multi-spectral imaging and automated visual measurement systems to allow fast and accurate determination of surface colour, texture and chemical composition of materials. LGC has conducted some preliminary investigations using spectral imaging in the field of durum wheat authenticity, and has shown it to be a rapid, cheap, non-destructive approach that requires no in-depth expertise or very expensive laboratory equipment, and has the potential to be used as a cost-effective point of test screening approach. We propose to further investigate the applicability of spectral imaging as a complimentary and alternative diagnostic test for food adulteration, in the areas of wheat and basmati rice authenticity. Proof of principle of the application of spectral imaging to these areas will be qualified in terms of initial assessment of performance characteristics including measurement uncertainty, repeatability, bias, and quantitative potential.
Objective No. Objective Description
01 Source material
Rice and wheat grains will be selected and sourced from appropriate suppliers.
02 Trial run and optimisation
Rice and wheat samples will be tested to facilitate optimisation of multi-spectral imaging devices in terms of varietal differentiation. An initial assessment of the method’s selectivity will be conducted.
03 Assay design
A range of sample concentrations (percentage adulteration) will be prepared to reflect typical adulterant levels and to challenge the spectral imaging’s applicability around the relevant legislative limit for food labelling.
04 Evaluation of imaging devices
Hand-held/bench-top spectral imaging devices at LGC will be evaluated for their potential to discriminate between Durum wheat and Common wheat, and for Basmati vs. non-Basmati rice. Blind samples from Objective No. 03 will also be assessed and used for this purpose.
05 External validation
Blind samples from Objective No. 03 will be independently analysed by a second laboratory using a state-of-the-art bench-top multi-spectral imaging device. Method validation data will be provided to demonstrate the fitness for purpose of the approach.
06 Report submitted to Defra
Delivery of report to Defra summarising the feasibility of using rapid and automated spectral imaging for testing food authenticity.
Project Documents
• EVID4 - Final project report : FA0136 EVID4 final report   (1295k)
Time-Scale and Cost
From: 2013

To: 2014

Cost: £32,458
Contractor / Funded Organisations
LGC Limited
Agro Food Quality