Scientists with the U.S. Department of Agriculture’s Agricultural Research Service (ARS) working at the Environmental Microbial and Food Safety Research Laboratory in Beltsville, Maryland, have developed and patented an advanced scanning system to be used in fresh produce packinghouses to detect certain kinds of exterior defects or contaminants.

According to an article published May 10, by Marcia Wood, Public Affairs Specialist for ARS, the team of ARS scientists designed “an experimental, cutting-edge optical scanning system that would use two different kinds of lighting, a sophisticated camera and other pieces of equipment” in order to examine fresh produce for quality and safety before it even reaches the grocery store.

By experimenting with apples, the scientists found that the system would detect cuts and bruises on the surface of the fruit as well as trace amounts of fertilizer and soil particles. In describing the process, Wood wrote:

The team’s system harnesses the capabilities of a type of camera known as a high-speed multispectral/hyperspectral line-scanner. Positioned above a conveyor belt, the scanner captures images of each fast-moving item, such as an apple. Each apple is exposed simultaneously to ultra-violet light from a UV fluorescent lamp and near infra-red light from a halogen lamp. The near infra-red light that bounces off the apple can be captured by an instrument known as a spectrograph and analyzed for tell-tale patterns of defects, while the UV light beamed on the apple can disclose the whereabouts of contaminants.

The system combines information from both forms of illumination into a single image with contaminant and defect results. When linked to a sorting machine, the system can signal the sorter to separate the problem apples from others.

Moon S. Kim, a biophysicist working on the project, explained that he and his team have been refining this system for the past few years. Their preliminary research was published in 2008, and, in 2010, Kim, along with engineers Yud-Ren Chen, Kuanglin (Kevin) Chao, and Alan M. Lefcourt received a patent for the system.

Currently, the scanning technology is limited to a 180-degree view of the produce item’s surface; however, Kim and his colleagues are hopeful that they will further improve the process to provide a complete 360-degree view, allowing produce packers to perform a thorough inspection for quality and safety.

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Image from the USDA Agricultural Research Service