Potential for Postharvest Disease in Tomato Fruit Infiltrated with Chlorinated Water. J. A. Bartz, Plant Pathology Department, University of Florida, Gainesville 32611. . Plant Dis. 72:9-13. Accepted for publication 29 June 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0009.

The incidence of disease associated with the infiltration of tomato fruits with water was reduced but not eliminated by adding 50–1,000 mg of free-chlorine per liter (ppm Cl₂) to the water. Bacterial soft rot and sour rot affected nearly 18% of fruits infiltrated with water containing 1,000 ppm Cl₂ and then stored for 2 wk at 24 C. Addition of chlorine (sodium hypochlorite) to water enhanced the infiltration of submerged fruit. Nearly 40% of fruit treated with 100–1,000 ppm Cl₂ absorbed 0.5 g or more of water compared with just 5% of those similarly treated with water alone. Water uptake increased with chlorine concentration, period of immersion, and depth of immersion. Disease incidence increased as chlorine concentration decreased. Under conditions that simulated commercial handling, water uptake was affected more by the period of immersion, 2–60 min, than by immersion depths of 1–15 cm or concentrations of 0–250 ppm Cl₂. Appropriate chlorination practices should control postharvest fruit rots; however, chlorination increases the potential for infiltration, and infiltrated fruit are likely to become diseased. Therefore, factors responsible for infiltration, such as the depth and period of immersion, must be controlled.

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