As a secondary measure of performance, the variation observed within printed arrays was also considered. Coefficient of variation (CV) values were calculated from fluorescence images, with a performance threshold of <20% being implemented. Pacific Blue, Cy3, and Cy5-labelled baseline microarrays exhibited CV values of 7.0, 17.6, and 7.0, respectively -all within the acceptable range (Figure ). Comparatively, the CV value of FAM-labelled baseline microarrays was 26.1. Higher variation here was attributed to unintended transfer of PDMS residue onto the polyethylene substrate during micro-contact printing, which causes non-specific fluorescence at this wavelength. When overlaid with foods, significant changes in CV values were observed (Figure ). Specifically, Pacific Blue-labelled microarrays exhibited very high CV values of 50.0, 55.0, and 57.9 with overlaid lettuce, beef, and chicken, respectively. Thus, while these microarrays retained high SNR values when imaged with target foods -owing to their high baseline fluorescence intensity, their high variability limits their suitability for biosensing. Recognizing that Pacific Blue offers comparatively low stability, it is likely that interactions with complex food matrices induced variable degradation of the label. FAM-labelled microarrays offered better consistency, but still surpassed the <20% performance threshold, with CV values of 26.3, 26.1, and 21.5 with the three respective food products. Opposingly, Cy3 and Cy5 offered values consistently below the set threshold, with Cy3 offering CV values of 16.9, 19.9, and 17.6 for the three respective products, and Cy5 exhibiting values of 7.0 and 8.2 for beef and chicken, respectively.