POSTHARVEST ISSUES IN BLUEBERRY AND CRANBERRY AND METHODS TO IMPROVE MARKET-LIFE

Abstract

Maximizing quality and extending market life of fresh blueberries and cranberries adds value to the fruit by enabling access to new markets. Fruit quality loss during postharvest handling is primarily the result of decay, physiological breakdown, physical abuse, and dehydration. Fruit must be of high initial quality to maximize storage life. Initial quality is dependent on many factors including cultivar, cultural practices, growing environment and harvest practices. Following harvest, blueberry fruit must be cooled and held near 0°C for maximum market life. However, the optimum storage temperature for cranberry fruit is less clearly defined and may range from 0 to 7°C. Maintaining a high relative humidity of 95% or greater minimizes weight loss and shrivel of blueberries, but can result in increased decay and physiological breakdown in cranberries. A RH of about 80% is recommended to maximize cranberry storage life. Controlled or modified atmospheres reduce decay of blueberries with optimum concentrations of CO2 ranging from 10% to 12%. Reduced O2 concentrations of 1% to 2% have been recommended but there is little evidence that O2 reduction is beneficial. Unlike blueberries, the storage life of cranberries does not benefit from modification of CO2 or O2 concentrations. Many other postharvest treatments have been attempted to extend the storage life of blueberry and cranberry fruit including heat, UV light, ozone and fumigation with various antimicrobial compounds. However, the benefit of most of these treatments has been limited and often inconsistent. The use of postharvest technologies to optimize marketing of high quality fresh fruit is discussed. INTRODUCTION The challenge in the postharvest management of fresh blueberry and cranberry fruit is maintaining fruit quality. If quality is maintained, market life can be extended, opening new market opportunities and adding value to the fruit. However, blueberry and cranberry fruit are perishable and are subject to postharvest decay, physiological breakdown, physical damage, shriveling/water loss and decline in sensory quality. To optimize quality for the market, high quality fruit must be handled properly during harvest, storage, packaging, transport, and marketing. The quality of fruit reaching the market is dependent on the quality of the fruit harvested from the field, as well as how it is handled during and after harvest. Therefore, in this paper I will address the impact of preand post-harvest factors on the quality of fresh blueberries and cranberries, with an emphasis on the utilization of postharvest technologies to maintain fruit quality.