Harvesting

Most fresh fruits and vegetables are extremely perishable. The safety and quality of the produce when it reaches the retail market is strongly influenced by the safety and quality of the produce at harvest. Additional factors that affect the safety and quality of fresh produce at the market include handling, storage temperature, transportation conditions, and the time period between harvest and consumption.

Maintaining safe, high-quality produce with an adequate shelf-life depends on both the pre-harvest factors discussed earlier and the control measures taken throughout the distribution chain. This chain begins with harvesting the produce. The choice of harvesting method depends on the produce characteristics. Mechanical harvesting is recommended for produce that can withstand physical handling.

For commodities destined for the fresh market, integrity and appearance are important, and manual harvesting is therefore widely used. Most fruit is almost exclusively harvested manually. With manual harvest, worker hygiene is especially important since there is a great deal of hand contact with the product that could lead to contamination. Proper sanitation of harvest tools is also critical to product safety.

Physical Damage

Physical damage caused during harvesting may lead to:

• Water loss
• Increased respiration rate
• Initiation of ethylene synthesis
• Fruit discolouration
• Penetration of micro-organisms

In-Field Packaging Operations

The following is recommended for products packed in the production field:

• All workers involved in field packing operations must follow good hygiene and sanitation practices.
• Avoid the direct contact of packages, containers, or products with the soil.
• All containers, baskets or empty boxes should be clean and free from visible signs of dirt, oil, grease and chemical contaminants.
• Packing containers should be stored in a clean dry place away from the field and should be transported and handled with the same sanitary considerations.

Post-Harvest Water Quality

Water is a key to a number of post-harvest operations. It is used in dump tanks to reduce physical injury as bins or picking trailers are emptied onto a packing line. It may be used for rinsing at any point on a packing line. It is needed for mixing solutions of waxes and fungicides. Hot water treatment is also used as a quarantine measure for pest control.

Water quality is important in reducing contamination during post-harvest cooling, washing and sanitising operations. The water used for post-harvest operations should be potable and free of disease-causing organisms. Water taken and used directly from rivers or holding ponds should not be used for post-harvest washing or cooling.

Practices that are used to reduce the risk of contamination of produce by postharvest processing water are as follows:

• Perform periodic water sampling and microbial testing.
• Follow appropriate guidelines for packhouse water sanitation.
• Change water as necessary to maintain sanitary conditions.
• Clean and sanitise water contact surfaces, such as dump tanks and wash tanks.
• Install backflow devices and legal air gaps to prevent contamination of clean water with potentially contaminated water.
• Routinely inspect and maintain equipment designed to assist in maintaining water quality, such as chlorine injectors, filtration systems, and backflow device.s

Cooling Considerations

Immediately after harvest, the temperature of the fresh produce is high. To extend the shelf-life and quality of fresh fruits and vegetables, products are generally cooled within 24 hours after harvesting. Heat elimination is commonly applied to highly perishable commodities such as fruits. There are many different types of cooling systems available.

Methods that are commonly used to cool fresh produce include:

• Room cooling
• Forced air cooling
• Hydro-cooling
• Package icing
• Vacuum cooling

Of the commonly used commercial cooling methods, the ones using air and vacuum present the lowest risk for contamination. However, the air introduced in the cooling systems can represent a potential microbial hazard. Microorganisms found in dust and tiny water droplets can be introduced onto products using these cooling systems. Such micro-organisms can come from outside dust, soil, equipment, and waste products. These micro-organisms cannot develop in the air, but air can serve as the vehicle through which they can reach the product.

Cooling methods using water and ice as the cooling mediums have the greatest potential for contamination of fruits and vegetables. Water and ice used for cooling operations are potential contamination sources. Water used in hydro cooling systems and for ice making should be potable and ice should be made and held under sanitary conditions.

Click here to view a video that explains harvesting practices.

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