Protecting the food supply chain from farm tofork: Utilizing SERS and portable Ramanspectroscopy

Ensuring food safety in various steps along the entire
food value chain is crucial to prevent undesired and harmful substances
entering the food humans consume. Pesticides and antifungal
agents used during growth, processing or along the logistic
chain from the field to the consumer can be toxic causing a
range of symptoms from stomach pain to the death of the consumer
even at trace levels of concentrations. To prevent dangerous
additives and contaminants entering the food chain governmental
restrictions on a large number of hazardous components
have been put into place and are tightly monitored. For a large
number of tests complex and sophisticated equipment is required
along with time consuming sample preparation steps, not permitting
instantaneous sampling of the specimen at the point of measurement
or in a timely manner. In order to become a commercially
applicable technique, the complexity of the sample preparation
and the analysis routine needs to be simplified without losing
performance in terms of identification and quantification of
the dangerous contaminants. Raman spectroscopy is a technology
to allow for quick and rigid analysis of materials without a
large amount of sample preparation. The use of surface enhancement
of the Raman signal by means of gold or silver nanoparticles
would allow for taking this measurement to the field with high
accuracy for even small concentrations. The high cost and poor
reproducibility of commercially available substrates has so far
limited the successful application of SERS measurements along
the food value chain. The use of an affordable handheld Raman
instrument with mass-producible SERS substrates will be
described in the frame of the contribution with respect to requirements
imposed at various stages along the food value chain.