Comparative Evaluation of Tomato Washing Using Treated and Untreated Water: Effects on Cleaning Efficiency, Microbial Reduction, and Quality Attributes

Abstract

Efficient washing of fresh tomatoes is essential to reduce surface contaminants and microbial load while maintaining product quality. The present study compared the effectiveness of hand washing using untreated potable water and treated water containing 100 ppm sodium hypochlorite on the washing performance and quality attributes of tomatoes. Washing trials were conducted at retention times of 1, 2, and 3 minutes under ambient conditions. Mechanical washing efficiency, microbial washing efficiency, bruise index, and colour attributes (L*, a*, and b*) were evaluated.

The results showed that washing efficiency and microbial reduction increased significantly (p ≤ 0.05) with an increase in retention time for both treatments. However, tomatoes washed with treated water exhibited significantly higher mechanical and microbial washing efficiencies compared to those washed with untreated water. The highest performance was achieved at a 3-minute retention time using 100 ppm chlorine-treated water, resulting in 87% mechanical washing efficiency and 88% microbial washing efficiency. The bruise index remained low (0.6) and was not significantly affected (p > 0.05) by the washing treatments, indicating minimal physical damage. Colour index values demonstrated improved colour retention in tomatoes washed with treated water.

Overall, the study concludes that hand washing with 100 ppm chlorine-treated water for a retention time of 3 minutes is an effective, safe, and economical method for improving the cleanliness and microbial safety of tomatoes without compromising quality. The findings provide practical insights for small-scale handling and post-harvest sanitation of fresh produce.