POTASSIUM BICARBONATE REDUCES POSTHARVEST DECAY DEVELOPMENT ON BELL PEPPER FRUITS

Bicarbonate salts are widely used in the food industry and have broad- spectrum antimicrobial activity. We investigated whether bicarbonate s alts can serve as alternatives to synthetic chemical fungicides for co ntrolling postharvest diseases of fruits and vegetables. Potassium bic arbonate (PBC) inhibited in vitro mycelial growth, spore germination a nd germ tube elongation of Botrytis cinerea and Alternaria alternata. Germ tube elongation was found to be more sensitive to elevated PBC co ncentrations than mycelial growth and spore germination, as measured b y EC(50) Treatment with PBC resulted in shrinkage and collapse of hyph ae and spores, and consequent inability of fungi to sporulate. PBC act ion was fungistatic rather than fungicidic. Dipping commercially harve sted sweet red peppers for 2 min in 1 or 2% potassium bicarbonate redu ced decay development after storage and shelf life simulation to a com mercially acceptable level of 5-8% compared with untreated or water-di pped controls. Higher concentrations of PBC (3%) significantly reduced fruit quality.