JAPA (Online) 2014
Vol 42 pg 35-60

A Simple DNA-Based Screening Approach for the Detection of Crop Species in Processed Food Materials

Eloise Busbya and Malcolm Burnsa,b

a)    LGC, Queens Road, Teddington, Middlesex, TW11 0LY, UK
b)    To whom correspondence should be addressed. E-mail: Malcolm.Burns@lgcgroup.com,
      Telephone: (+44) (0)208 943 7000, Fax: (+44) (0)208 943 2767

Summary

Ensuring that food manufacturers and suppliers are adhering to current EU legislation on labelling is important for preventing food fraud, enabling consumer choice and ensuring that ingredients are listed correctly in the interest of public health. This highlights the requirement for reliable and sensitive methods for detection and identification of ingredients, particularly those which may be allergenic. Molecular biology approaches including the Polymerase Chain Reaction (PCR) have become increasingly common for the detection of DNA targets in food. The aim of the present study was to design and demonstrate proof-of-principle for a simple end-point PCR and capillary electrophoresis (CE) system for the detection of a subset of crop species in processed foods and to demonstrate minimum good practice in the evaluation of such an approach. A system of this kind could be used as a screening approach in Official Control Laboratories.

PCR assays were designed based on taxon-specific gene targets from cotton, lupin, maize, soya and sugar beet. Primers were tested using authenticated positive control material and amplicons analysed using the Agilent 2100 Bioanalyzer. The five assays were optimised for simultaneous application using the same cycling conditions and their fitness for purpose demonstrated by applying them to a range of processed food materials.

The assays for lupin, maize and soya repeatedly amplified DNA from a range of processed food materials where the crop species were present on the ingredient list. The cotton and sugar beet assays showed no cross-reactivity with other crop species and demonstrated no false-positives when applied to the range of processed food materials, only producing a detectable response when in the presence of the target DNA sequence from the positive control. The present study was successful in developing a simple, singleplex lab-on-a-chip approach for the simultaneous detection of common ingredients in foods, the principles of which can be applied to various fields within the area of food authenticity testing.

Keywords

PCR, lab on a chip, screening, maize, soya, cotton, sugar beet, lupin, allergens

Full Text of Paper

 

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