The result: The overall product is a simple, low-cost batch of methods for the determination of chlorophenol and chloroanisole compounds in liquid food matrices. The product has been developed from the point of providing measurement solutions end-users in the wine industry, where chlorophenol and chloroanisole contamination of wine products is a particular problem. However, the solutions developed are wider than this example scenario, in that the product may also serve as a measurement tool for assessing target analyte levels in other liquidic food products, such as fruit juices and potable water, and with further development, any foodstuff that can be applied to the assay in liquidic form.
The assay procedure is compatible with food processing operations that have small, simple laboratories attached, as is the case in, for example, the wine industry. The assay is split into 2 distinct phases: sample preparation and immunochemical analysis, using the well-known technique of Enzyme Linked Immunosorbent Assay (ELISA). Sample preparation methods have been developed for both the chlorophenols and chloroanisoles based on either simple solvent extraction procedures, or by the use of simple stream distillation processes coupled to solid-phase extraction. These methods are simple to apply, requiring low-cost instrumentation and minimal operator training. Such sample preparation procedures are required to simplify the food matrix (wines for example are extremely complex materials) and to pre-concentrate the target analytes sufficiently to allow their subsequent detection by the ELISA method. Chlorophenols can impart unpalatable tastes and odours to wines at low part per million/upper part per trillion levels, whilst chloroanisoles have even lower sensory thresholds. Sample preparation methods have been developed for wines, bottle washings, packaging materials and corks, thereby offering the end-user means of conducting traceability studies to determine the source of the chlorophenol/ chloroanisole contamination.
The ELISA process itself is simple to perform and is amenable to multi-samples throughput the process is reliant on only very cheap, simple readily available instrumentation and can be performed by an operator with minimal training. Results can be readily interpreted allowing appropriate remedial processes to be immediately implemented. The benefit of the process over existing methods resides in cost, simplicity and the fact that the assay may be performed in simple, low-level equipped laboratories. The method is complimentary to the current GC-MS methods, in that the immunochemical systems can be used for screening purposes allowing data to be rapidly obtained. Suspect samples may be sent to a centralised facility for confirmatory analysis using validated standard instrumentation methods.