Development and evaluation of a mechanical carrot washing machine
Keywords:Benefit cost ratio, carrot, colour, capacity, microbial load
Vegetable production in Bangladesh has increased substantially (3 million tons) and ranked third position in the world. Root vegetable need to be cleaned before transporting from field to market. A base line survey was conducted on vegetables production, sorting, washing, and packaging in four vegetable growing districts such as Narsingdi, Bogura, Jashore, and Pabna district to generate baseline indicators which helped in developing a mechanical device for carrot washing. In all locations, root crops (carrot and radish) were washed manually by farmers to get better price. Manual method is drudgery, time consuming and unhygienic. A batch type carrot washing machine with holding capacity of 120 kg was designed and fabricated with locally available materials at Bangladesh Agricultural Research Institute, Gazipur. It was operated by an electric motor of 2.1 kW. Centrifugal water pump of 1.1 kW was used for water supplying. Washing period ranged from 5 to 7 minutes per batch. Washing and cleaning efficiency of the machine were 98% and 99% respectively. Washing improved the microbiological quality and safety of carrots. Washing cost of carrot was found to be 0.29 BDT/kg. Payback period and breakeven points of the washing machine were 39 days and 145 h/yr, respectively. Benefit cost ratio of washing was found to be 2.44. The price of the washing machine was BDT 220000.0 (US$2500). Machine saved by 67% cost and 47% time compare to conventional manual carrot washing method. Farmers and traders would be benefited using the vegetable washing machine in custom hire basis.