| | Determining the best method for pre-cooling fresh produce is essential for an effective, economic operation. Each type of fruit and vegetable has a preferred method for pre-cooling.
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The preferred method for a particular type of produce, however, may not be the most economic for a particular gardener. Most market gardens produce more than one type of produce. It is therefore important, in many cases, to choose systems that are sufficiently versatile for a wide range of produce.
Developing an integrated post-harvest system requires a detailed knowledge of each type of produce, especially the factors associated with produce spoilage and deterioration. Developing an integrated system also means having a thorough knowledge of harvest systems, handling methods, pre-cooling, curing, washing, grading, storage and marketing. With this information, the various types of produce can be grouped together into sub-systems and then individual systems.
The following possible process steps can be used as a guide in deciding on the best configuration for a system. Look at each step and the possible methods for each function for each type of produce. Then, list the methods in order of preference for each type of produce. Include potential new types of produce and upgraded processes.
- Harvesting
- Methods for handling at various process stages from field to market
- Washing
- Curing
- Pre-cooling
- Storage
- Washing
- Grading
- Packaging
- Handling method
- Shipping
- Marketing
Use the Figure D flow chart "general flow options for post-harvest operations" as an aid in identifying the necessary steps for each type of produce. Note: each step has several methods as possible options.
Arrange the types of produce in order of priority for each of the steps. This approach will help define the types of sub-systems to use.
In most cases, a pallet-based handling system will be used. Small operations can start with containers suitable for stacking on pallets, with a later upgrade to the pallet system. Large operations that handle produce in bulk from the field often use pallet systems after washing or grading or for shipping of packaged produce.
Handling systems must have at least the same capacity as the harvest systems. The same handling systems used for harvest are often used for curing, pre-cooling and storage.
Washing systems are generally specific to certain groups of produce. Grading is generally an integral part of the final wash systems, and packaging is generally an integral part of the grading systems.
The pre-cooling systems used, as discussed earlier, depend on the type of product and handling system used. The associated curing and storage requirements are similar to those for pre-cooling. Pre-cooling systems for highly perishable produce require refrigeration capacity that is sufficient to cool the produce at the rate it is harvested. Less perishable produce can be pre-cooled over a longer period, but the pre-cooling should be completed at least within a day of harvest to secure optimum quality.
Consider the use of ice as a source of refrigeration, especially for highly diverse types of operations. Ice can be used in forced air cooling, hydro cooling, top icing, slurry icing and chilling of wash water. It can also provide refrigeration for the short term storage and transport of highly perishable produce.
Curing systems are fairly specific to produce types, and heat is often required. In some cases, curing may even be done in the field.
Storage systems need to take into account the compatibility of produce. This situation includes temperature, humidity, air flow, sensitivity to storage gasses as well as production of odours detrimental to other produce. In most cases, storages used by market gardens need to be divided into rooms with separate controls for temperature and humidity. However, the same handling and shipping systems are often used for produce from separate storages.
Two main objectives in setting up the system:
- Minimize deterioration of product
- Minimize handling
Other objectives:
- Have designated and centralized handling areas for moving produce between the various operations. Minimize the storage of equipment and materials in the produce storage and processing areas.
- Lay out systems and equipment so that maintenance and cleanup are easily carried out.
- Provide ample drainage inside and outside the facility.
- Provide for expansion of storages and upgrading of processing areas.
- Floors and walls must be easy to clean and sanitize.
- Optimize use of refrigeration capacity.
These pointers should aid in the development of effective, efficient post-harvest systems for market gardeners in Alberta. |
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