Harvesting Horticultural Commodities and different harvesting systems.

Postharvest Horticulture
Quality in produce can be defined as the composite of characteristics that differentiates individual items within a commodity and have a significant influence in determining the level of acceptance by the consumer. High quality vegetables are one of today’s wonders with regard to the U.S. food supply. Locally produced vegetables, readily available seasonally have resulted in consumers demanding the same freshness and quality on a year round basis. Unfortunately, many Texas vegetable growers believe that once a high quality product is produced, their problems are over. In reality, their troubles could be just beginning. It has been estimated that more than 40% of perishable commodities are lost after production.

Fresh vegetables are extremely perishable and have relatively short shelf lives. They are living, respiring tissues that start senescing immediately at harvest. Freshly harvested vegetables are mostly comprised of water with most having 90 to 95% moisture content. Water loss after harvest is one of the most serious postharvest conditions. Consequently, special effort is required to reduce the effects of these naturally occurring processes if quality harvested in the field will be the same at the consumer level.

Maintaining Quality
Special skills are required for proper harvesting, handling, grading and packaging of vegetables in order to insure optimum produce quality at the marketplace. It makes little difference what the quality is at harvest if it is reduced by poor handling, packaging or storage conditions. Price received for produce is determined by quality at the marketplace. Variables consumers perceive as a reflection of produce quality are ranked in order of preference as follows: crispness and freshness, taste, appearance and condition, nutritive value, and price. Studies have shown that two factors normally enter into consumers purchase decisions: competition between like items on the display shelf, and, the acceptability of the item in reference to his or her standard for that item in reference to the above variables. Consequently, producer who are able to produce and package their produce in such a way to enhance these variables are the most successful in the market place.

Because of the perishable nature of vegetables, harvesting and handling speed is of utmost importance as soon as harvest maturity has occurred. Every producer should have products reach the end consumer as quickly as possible. Unfortunately, they have no control once the produce leaves their farm or packing sheds. However, maximum speed and efficiency in handling produce on the farm or at the shed will help maintain quality. Consequently, a grower must be prepared to operate in advance of the actual harvest operation. Preharvest preparation should include lining up sufficient labor, supplies (containers and packaging items), cleaning the grading/ packing shed, and determining if all equipment is operable. Once the produce reaches harvest maturity, delays for any reason can result in major quality and crop losses. In addition, the nutritive content of produce is not static either. Biosynthetic and degradation reactions will even continue to occur during handling and storage.

Techniques to extend postharvest shelf life:

reducing respiration by lowering temperature
slow respiration by maintaining optimal gaseous environment
slow water loss by maintaining optimal relative humidity
variety selection
Postharvest handling includes all steps involved in moving a commodity from the producer to the consumer including harvesting, handling, cooling, curing, ripening, packing, packaging, storing, shipping, wholesaling, retailing, and any other procedure that the product is subjected to. Because vegetables can change hands so many times in the Postharvest sector, a high level of management is necessary to ensure that quality is maintained. Each time someone fails to be conscientious in carrying out his or her assigned responsibility, quality is irreversibly sacrificed.

Maintaining produce quality from the farm to the buyer is a major prerequisite of successful marketing. The initial step required to insure successful marketing is to harvest the crop at the optimum stage of maturity. Full red, vine-ripened tomatoes may be ideal to meet the needs of a roadside stand, but totally wrong if the fruit is destined for long distance shipment. Factors such as size, color, content of sugar, starch, acid, juice or oil, firmness, tenderness, heat unit accumulation, days from bloom, and specific gravity can be used to schedule harvest. Vegetable producers should gather as much information as possible on maturity indices for their particular commodities. The result of harvesting at an inappropriate stage of development can be a reduction in quality and yield. Table 25 of the Appendix lists the optimum harvest maturity stages for most vegetables produced in Texas.