The presence of low-density organic foreign objects, such as insects, in food is extremely difficult to detect using conventional metal detectors and X-ray inspection systems. Therefore, the aim of a recent study, carried out by a group of Japanese researchers (Taketoshi et al., 2025), was to develop a single-pixel imaging method in the visible and near-infrared (Vis-NIR-SPI) to detect such objects within chocolate.

The advantages of Vis-NIR light include its ability to analyse samples non-destructively and to measure multiple components simultaneously and quickly, while SPI is robust against background noise, high dispersion and high equipment costs.

The results show that the proposed system effectively reduces the scattering effects of the product, allowing the acquisition of information that goes beyond the capabilities of a CCD camera, and that only 1 uncontaminated sample out of 100 was erroneously classified as contaminated, achieving an overall accuracy of 99%.

This high level of accuracy underlines the potential of the Vis-NIR-SPI method to provide reliable detection while maintaining product integrity. In addition, the proposed method is cost-effective, offering a practical and efficient solution to improve quality control processes and consumer confidence in the food industry.

Bibliography: H. Taketoshi et al., Foods, 14, 2025, 1-13.