Automatic Inspection System for Processing Tomatoes

Abstract. In California, processing tomatoes are inspected after harvest and prior to processing in order to assess their maturity, fruit quality, and possible inclusion of defects. As part of the official grade, tomatoes are inspected for the color, pH and soluble solids content of the comminuted raw fruit in a random sample obtained from each truckload. A fully automated system for measuring the internal quality of processing tomatoes for use at processing tomato inspection stations in California was developed and tested. The automatic inspection system developed in this study was able to complete the entire cycle (sample preparation, fruit quality measurements, data transfer, fruit disposal and system cleanup) in 60 seconds, which compares favorably with the current ~3 minute time cycle to complete the current grading procedure. The only step not fully automated was the manual removal of material other than tomatoes (e.g., stems, leaves, and soil) before comminution and the loading of the sample into the comminution chamber. The system employed a programmable logic control system to actuate the vacuum blending system, pneumatic flow controls, quality measurements, data acquisition and display and cleaning cycles. The fruit quality measurements obtained by the fully automated system were compared to the standard official measurement methods currently in use in the official inspection program. The safety features, ergonomics and timesavings achieved by the system are also described.