Ronald P. Haff

A high-resolution real-time x-ray imaging system was assembled using a low-energy, high-current x-ray source,a low-energy x-ray image intensifier, and a CCD camera interfaced to a PC. Overall system resolution was measured at 5 linepairs per mm (100 .m), sufficient for identifying infestations of the granary weevil, Sitophilus granarius (L.) in kernels of wheat.The field of view for imaging of the system was 6 cm2, large enough to image approximately 350 kernels of grain in a single frame.The exposure time for a single frame was 149 ms, yielding a maximum potential throughput rate of around 2500 kernels persecond. For this study, 1500 wheat kernels were x-rayed, both on film and with the system described above. Of the imagedkernels, 682 contained infestations ranging in maturity from the egg to the adult life stage of the granary weevil, while 818 wereuninfested. Both film and digital images were presented to human subjects to compare recognition of the infested kernels.Overall recognition results averaged 84.4% for the images from the intensifier system vs. 90.2% for the film observations.However, when considering only infestations more advanced than the 3rd larval instar, errors for both sets of images fell below2% and were not significantly different.

The gluten protein found in a variety of cereal grains is a food allergen that can elicit a spectrum of immuno-inflammatory responses in people. Consumer awareness has prompted changes in food labeling requirements, expanded gluten-free food product availability and increased demand for effective gluten testing methodologies. To meet the challenges associated with gluten testing from diverse and complex foods we developed a lateral flow immunoassay (LFIA) using a pair of novel gliadin monoclonal antibodies (MAbs). Using a visual gold reporter, we show sensitive gluten detection (150 ng/mL) from complex food substrates using a fast (<5 min) and easy testing methodology. In this report we characterize the binding properties of a cohort of newly generated gliadin monoclonal antibodies suitable for gluten detection using multiple assay formats and introduce a novel plug-n-play test strip platform with integrated test components in a single-use format.

A nondestructive method for detection of translucency, a physiological disorder in pineapple, would be beneficial to the industry. Ninety-two pineapples were imaged with X-ray to determine whether translucency could be detected. After imaging, each pineapple was cut open to determine the true level of the disorder and rated on a scale from 1 (no translucency) to 5 (extremely translucent). The X-ray images were inspected by human subjects who evaluated them as either good or bad based on the appearance of translucent and nontranslucent pineapples in training images. The results show a high correlation (R2 = 0.96) between the likelihood of a sample being rated as good and the actual level of translucency observed. Samples with no translucency were correctly identified 95% of the time, while those with extreme translucency were correctly identified 86% of the time. The results indicate that X-ray imaging is a useful method for selecting either pineapples that are most likely to be free of translucency or those that are most likely to be extremely translucent.