This focusing-free system will image food samples flowing in a transparent micro-channel under illumination of RGB lasers through a pinhole, and yield their 3D chromatic structures in real-time using hologram-based reconstruction algorithms. The estimated cost of the proposed system is less than HK$30,000 and its speed is over 1,000 times faster than the existing methods. The proposed system, if developed successfully, will become a key technology to safeguard food safety against the virulent and ever-evolving serogroups of E. coli and fecal contamination in our society, and fulfill the needs of rapid and low-cost E. coli detection from food industry and point-of-care testing (POCT).

• Novel design.
• Good performance.