An in-house study at RIKILT (NL) using carotenoid HPLC-DAD profiling combined with k-nearest neighbour classification chemo-metrics reliably identifies production system (i.e., organic vs. non-organic) for chicken eggs. The proposed international inter-laboratory trial aims to demonstrate if this approach is robust by applying the method in different laboratories and thereby determine its suitability for routine analysis. The method developed for verification of organic eggs is one of only a few for verification of organic produce with any degree of success. Many EU and non-EU countries could potentially benefit from this method and, furthermore, the concept could be applied to other foods. Currently, the model is based on Dutch eggs and validation requires testing with eggs from other countries. It is proposed to carry out a study to validate the method for eggs sourced from MoniQA partners’ countries of origin.
Organic production benefits from fair competition and sustained consumer confidence, which can only be assured with robust methods able to determine if claims are accurate. Traditional analytical strategies guaranteeing quality and uncovering adulteration have relied on determination of amounts of marker compound(s) and subsequent comparison with those established for equivalent material. Since unique markers that allow discrimination between organic and conventional produce are scarce, selective fingerprinting (profiling) combined with chemo-metrics is a more promising approach. In the RIKILT study, the proof-of-concept set for the model was composed of eggs from 24 organic farms, 12 free range and 12 barn farms in the Netherlands. The identity of organic, free range and barn eggs were predicted with success rates of 100%, 100%, and 84%, respectively. The identity of eggs determined using an additional market test set with eggs from 12 organic, 12 free range and 12 barn farms originating from the Netherlands and New Zealand resulted in the correct classifications for 35 of 36 samples. These results indicate this fingerprint approach is a promising tool for analytical verification of production systems of eggs. A manuscript based on the results of this study has been accepted for publication in Food Chemistry.
Planned experimental design:
- Egg collection – eggs from organic and conventional (free range and barn) productions will be collected by MoniQA partners. Each partner will collect at least nine eggs from eight organic farms, four free range farms and four barn farms as well as feed for the laying hens, which may provide some additional information
- Yolk preparation – yolks and whites will be separated and three samples from three pooled yolks prepared for freeze-drying
- Transport – after freeze-drying, samples will be sent to RIKILT (NL)
- Analysis – RIKILT will analyse the samples and apply the statistical models, which were built on Dutch eggs. The results will be shared with MoniQA partners and published
- Sharing analytical and statistical experience – at the end of the study, partners will be invited to RIKILT (NL) to develop expertise with the analytical and statistical procedures involved to allow them to build their own database as well as adding to the existing Dutch resource. If the method can be used in other countries, an inter-laboratory comparison to validate the analytical aspects may follow.
Contact: Saskia van Ruth (saskia [dot] vanruth [AT] wur [dot] nl) RIKILT, NL
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