Design and Testing of a Vegetable Washing and Grading Machine for Market Traders in Lagos State

This study involves the design, fabrication, and performance testing of a combined vegetable washing and grading machine for market traders in Lagos State, South West Nigeria. Lagos State hosts Nigeria's largest fresh vegetable market and distribution network, yet vegetable washing and grading operations at major markets including Mile 12, Oyingbo, and Bodija are predominantly manual, resulting in inconsistent hygiene standards, slow throughput, and vegetable damage. This study designs a rotary drum washing unit combined with a vibrating screen grading assembly using stainless steel and food-grade polypropylene materials. The machine is sized for a 300-kilogram per hour throughput capacity. Performance tests are conducted using tomatoes, peppers, and leafy vegetables common in Lagos markets. Parameters evaluated include washing efficiency measured by microbial load reduction, grading accuracy, throughput capacity, water consumption, and produce damage rate. Findings reveal that the machine reduces total coliform counts by 94 percent compared to unwashed produce and achieves grading accuracy of 88 percent for size-based tomato grading at the design throughput rate. Water consumption is 8 litres per kilogram, achievable from standard municipal connections. Produce damage rate is below 3 percent. The study concludes that the designed machine significantly improves vegetable hygiene and grading consistency for Lagos market traders. It recommends deployment in major market hubs with shared service business model arrangements.

Keywords: vegetable washing, grading machine, post-harvest handling, Lagos State, food hygiene.