EFFECT OF OZONE AND STORAGE-TEMPERATURE ON POSTHARVEST DISEASES AND PHYSIOLOGY OF CARROTS (DAUCUS-CAROTA L)

Effects of ozone and storage temperature on carrots and two postharvest pathogens-Botrytis cinerea Pers. and Sclerotinia sclerotiorum de Bary-were investigated. Pathogen-inoculated and uninoculated whole carrots were exposed to an ozone concentration of 0 (control), 7.5,15,30, or 60 mul.liter-1. Treatment chambers were flushed with a total flow rate of 0.5 liters.min-1 (air and ozone) for 8 h daily for 28 days. The experiment was repeated twice at storage temperatures of 2, 8, and 16C. The residual ozone concentration (ozone supplied-exhausted and reacted ozone) increased with ozone supply concentration but was less at higher storage temperatures. A 50% reduction of daily growth rates of both fungi at the highest ozone concentration indicated that ozone was fungistatic. Carrot respiration rate, electrolyte leakage, and total color differences increased with ozone concentration. Ozone-treated carrots were lighter (higher L* values) and less intense (lower chroma values) in color than control carrots.