Causes and Sources of Postharvest Problems

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

3. 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.

4. 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)

5. Propping heavy limbs of fruit trees

6. 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.

7. Inappropriate field containers

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

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

10. 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).

11. Wash water sanitation

12. 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.

13. 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.

14. Inappropriate packages

15. 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.

16. 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.

17. 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.

18. 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.

19. Airport delays

20. 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.

21. Rough handling is common

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

23. Environmental factors influencing rate of deterioration • TEMPERATURE • Relative humidity • Atmospheric composition • Ethylene • Other factors