Causes and Sources of Postharvest Problems Common practices and conditions affecting postharvest losses, produce quality and food safety

Pre-Harvest Inadequate planning regarding planting and harvesting dates, or growing varieties that mature when market prices are lowest. Production of varieties with high yields but short postharvest life or susceptibility to postharvest pests and diseases. Use of poor quality planting materials.

Pre-Harvest continued Over-fertilization of vegetables with nitrogen. Poor orchard and field sanitation leading to latent infections and insect damage. Lack of pruning, propping limbs and/or thinning fruits leading to small sized fruits with non-uniform maturation. Lack of pest management (spraying for insect or fungal control, bagging)

Propping heavy limbs of fruit trees

Harvest Harvesting at improper maturity leading to lower eating quality, failure to ripen or excessive softening. Use of rough and/or unsanitary field containers. Harvesting during the hot hours of the day. Rough handling, dropping or throwing produce, fingernail punctures.

Inappropriate field containers

Harvest continued Leaving long or sharp stems on harvested produce. Long exposure to direct sun after harvesting. Over-packing of field containers.

Curing Lack of curing or improper curing of root and tuber crops before postharvest handling, packing and storage. Improper drying of bulb crops.

Packinghouse Operations Lack of proper sorting. Lack of cleaning, washing or sanitation. Rough handling. Improper trimming. Misuse of postharvest treatments (over- waxing, inadequate chlorine in wash water, misuse of hot water dips for pest management).

Wash water sanitation

Packinghouse Operations Use of inappropriate chemicals or misuse of registered compounds. Long delays without cooling. Lack of accepted and/or implemented quality grades or standards for commodities. Lack of quality inspection.

Packing and Packaging Materials Use of flimsy or rough packing containers. Lack of liners in rough baskets or wooden crates. Over-use of packing materials intended to cushion produce (causing interference with ventilation). Containers designed without adequate ventilation.

Inappropriate packages

Packing and Packaging Materials Over-loading containers. Use of containers that are too large to provide adequate product protection. Misuse of films for M. A. packaging, over-reliance on MAP versus appropriate temperature management.

Cooling General lack of the use of any methods of cooling during packing, transport, storage or marketing of fruits or vegetables. Inadequate venting in containers. Improper stacking of pallets on FA coolers. Inadequate dwell time in Hydro-coolers.

Storage Poor sanitation Inadequate management of temperature and relative humidity. Over-loading of cold stores. Stacking produce too high for container strength. Mixing types of produce with different temperature/RH requirements. Lack of regular inspections for pest problems, temperature/RH mgmt.

Transportation Over-loading vehicles or marine containers. Use of bulk transport or poor quality packages leading to compression damage. Poor palletization practices. Lack of adequate ventilation during transport.

Airport delays

Transportation continued Lack of air suspensions on transport vehicles. Rough handling during loading. Lack of cooling during delays. Ethylene damage and/or chilling injury resulting from transporting mixed loads.

Rough handling is common

Causes of deterioration n Metabolic changes (ripening, senescence) n Growth and development n Bruising and other mechanical injuries n Moisture loss n Physiological breakdown n Decay

Environmental factors influencing rate of deterioration n TEMPERATURE n Relative humidity n Atmospheric composition n Ethylene n Other factors