View source for Pre-cooling of Agricultural Products

= Overview<br/> =

Pre-cooling refers to the rapid removal of field heat shortly after the harvest of a crop. Field heat can be defined as the difference in temperature between the temperature of the crop harvested and the optimal storage temperature of that product. In general the temperature should be cooled down till it reaches 88% of the existing difference in temperature and its optimal storage temperature. Field heat should be removed as fast as possible since, for most produce, an hour delay at field conditions of about 35°C will lead to a loss in shelf-life of about 1 day – even at optimal storage conditions<ref name="National Horticulture Board, 2010">National Horticulture Board (2010) Cold Storage for Fresh Horticulture Produce Requiring Pre-cooling before Storage. Haryana: Cold Chain Development Centre National Horticulture Board </ref> <ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref>.<br/>

Nevertheless, due to biological factors, the importance of rapid pre-cooling varies. According to the Indian Board of Horticulture<ref name="National Horticulture Board, 2010">National Horticulture Board (2010) Cold Storage for Fresh Horticulture Produce Requiring Pre-cooling before Storage. Haryana: Cold Chain Development Centre National Horticulture Board </ref>, especially grapes, mandarins, berries, cherries, leeches, melons, stone fruits, sapotas, okra, tomatoes, capsicum, chilli peppers, eggplant, cucumbers, green beans, peas, and spinach should be rapidly pre-cooled, whereas other, less perishable produce is made up of mangoes, papaya, guava, green bananas, pomegranates, radish, cabbage, cauliflower and carrots. More detailed information about adequate pre-cooling methods for various fresh produce items can be found [http://www.ba.ars.usda.gov/hb66/contents.html here].

According to the [http://www.fao.org/home/en/ FAO], precooling is “amongst the most efficient quality enhancements available” and is regarded “as one of the most value-adding activities in the horticultural chain”.<br/>

<u>Pre-cooling benefits include:</u><br/>

*lowering the required workload of a cold storage since optimum storage temperature is reached more quickly<br/>
*restricting and minimizing respiratory activity, thereby conserving the weight of the produce, and enzymatic degradation of the produce harvested; thus preventing softening, water loss and wilting<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>
*preventing microbial growth, such as bacteria and fungi thereby decreasing the rate of decay<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>
*decreasing rate of ethylene production and the impact on ethylene sensitive produce<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>
*delaying chilling injuries for certain fruits<ref name="Agriculture Information Bank, 2009">Agriculture Information Bank (2009) Pre-cooling of Fruits and Vegetables. [Online] Available from: http://agriinfo.in/default.aspx?page=topic&superid=2&topicid=2048 [accessed 29th July 2014]</ref>
*increasing the daily intake into storage facilities which should not exceed 10% of its cooling capacity if produce is not pre-cooled<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>

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<u>There are several methods that can be chosen to pre-cool produce. Which method is the most suitable choice depends on various factors of which some are listed below:</u><br/>

*'''Produce characteristics''': characteristics of produce, such as chilling sensibility or the need for rapid heat removal, lead to differing cooling requirements making methods more or less suited. Products also differ in their flow capacity; the faster products can be cooled down, the better. Some methods cannot be tolerated by some fruits and vegetables, e.g. if they cannot get in contact with water<br/>
*'''Packaging''': the way produce is being packaged makes precooling methods more or less suitable
*'''Scale''': size of operations/amount of produce to be cooled
*'''Efficiency''': depending on the circumstances some methods will be more energy efficient than others
*'''Skilled labor''': methods require various levels of skilled and trained personnel. The availability of such trained personnel has to be considered
*'''Economic viability''': the price of precooling methods differ and have to be considered. This is true with regards to investment as well as running costs, e.g. electricity. In general, the cost of the pre-cooling method has to justifiable with regards to product volume and the increase in product value in order to make economic sense<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>

Regardless of which method is used, the process should always be monitored in order to ensure that precooling is achieved in the most efficient way. Depending on method and product at hand, produce will cool at different rates.<br/>

[[Pre-cooling_of_Agricultural_Products#toc|►Go to Top]]

= Methods =

In general, there are three different methods to pre-cool produce, using either air, water or the creation of a vacuum.

<u>Below each method and possible variations are shortly explained:</u><br/>

*[[Pre-cooling of Agricultural Products#Shade|Shade]]
*[[Pre-cooling of Agricultural Products#Air Cooling|Air Cooling]]
*[[Pre-cooling of Agricultural Products#Water Cooling|Water Cooling]]
*[[Pre-cooling of Agricultural Products#Ice Cooling|Ice Cooling]]
*[[Pre-cooling of Agricultural Products#Vacuum Cooling|Vacuum Cooling]]

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[[Pre-cooling_of_Agricultural_Products#toc|►Go to Top]]<br/>

== Shade ==

The simplest, most low cost and low technology option to reduce field heat is to move produce to a deeply shaded area directly after harvest. The temperature in packing houses, with roofs that are light colored or reflective, can reduce temperatures as much as 20°C<ref name="USAID, 2009">USAID (2009) Empowering Agriculture – Energy Options for Horticulture. [Online] Available from: http://ucce.ucdavis.edu/files/datastore/234-1386.pdf</ref>.

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== Air Cooling ==

Use of refrigerated air in a conventional cold storage room, a special pre-cooling room, a funnel cooler, or a forced air cooler. Air cooling can be subdivided in the methods of room cooling and forced-air cooling:

<u>'''Room cooling'''</u>: produce is put into a cold (refrigerated) room<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref><br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 128px;" | Advantages
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Very energy efficient if designed properly<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Challenges</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Very slow<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Produce has to be stacked properly so that the cold air can flow through the stacks<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Adequate for</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">not for produce requiring immediate and rapid cooling<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">fruits rather than vegetables</span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">not for produce which is stored in bulk bins or containers since the temperature of produce located towards the middle of the storage bin will increase because heat generation through respiration is likely to outpace the speed heat removal<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span><br/><span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">citrus, apples stored under controlled atmosphere conditions, which however, will not have optimal quality if this method of pre-cooling is used<ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref></span>
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<span style="line-height: 1.5em; font-size: 0.85em;"></span><span style="line-height: 1.5em; font-size: 0.85em;"></span>

<br/><u>'''Forced-air cooling''':</u> a fan is used to drive air through packed produce within a refrigerated room. The usage of the fan increases the cooling rate compared to basic room cooling. Produce should be packed and stacked in a way that allows air to flow through fast<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref><br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Advantages</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Faster than room cooling<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Challenges</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Time required for cooling depends on air temperature<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Adequate for</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Most widely used and adaptable form of pre-cooling<ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref></span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Used for fruits and fruit-type vegetables<ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref></span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">avocado, cucumber, melon, pumpkin, banana, mango, coconut, eggplant, okra, grapes, orange, strawberry, brusselsprouts, grapefruit, papya, squash, carambola, guava, passion fruit, tangerine, cassava, kiwi, pepper tomato, cherimoya, persimmon, pineapple, pomegranate, litchi, breadfruit<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|}

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== Water Cooling ==

Uses water to take up the heat from harvested produce<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>. Cold or chilled water is sprayed on produce or the produce is dipped into it. Water should be able to flow through the produce rather than around it<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref><span style="line-height: 1.5em; font-size: 0.85em;">.</span><br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Advantages</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Heat is removed rapidly and about 15 times faster than if air was being used since water is a better heat transfer medium<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref> <ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref></span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">can be done with a refrigerated CaCl2 solution to prevent storage disorders in fruits</span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">no moisture loss<ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref></span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">least expensive pre-cooling method<ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref></span>
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Challenges</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Need for clean and sanitized water to prevent microbial contamination<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Energy efficiency is lower than with room and forced air cooling<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Adequate for</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Commodities that can tolerate becoming wet<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 128px;" | <br/>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Generally used for stem and flower type as well as root vegetables, and some tree fruits<ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref></span><br/><span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">celery, peas, asparagus, Chinese cabbage pomegranate, beet, cucumber, broccoli, eggplant, radish, Brussels sprouts, green onions, spinach, cantaloupe, kiwi fruit, squash, carrot, leek, sweet corn, cassava, orange, melon and cauliflower<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref> <ref name="Thompson">Thompson, J. F. (n.d.) Pre-cooling and Storage Facilities. [Online] Available from: http://www.ba.ars.usda.gov/hb66/precooling.pdf</ref></span>
|-
| style="width: 128px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Equipment required</span>
| style="width: 637px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Packaging equipment: wire-bound wooden crates, waxed fibreboard cartons, mesh poly bags and bulk bins, pallets (need to be stacked in a way that water can enter packages)<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
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== Ice Cooling<br/> ==

Ice is used to remove heat from fresh produce.<br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Advantages</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Advantageous if packages are too dense to be cooled with air<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Removes heat rapidly<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Continues to remove heat through absorption while melting</span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Usable during transport, distribution and storage<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Challenges</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Ice used must not contain any chemical, physical or biological hazards<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/fckLR</ref></span>
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| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Inefficient since about half of the cooling effect is lost to heat exchange with the environment instead of actually contributing to cooling the produce (USAID, 2009)</span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Depending on the proximity of the ice-making facility and the availability of insulating packaging, losses during the transport to the cooling facility will occur (USAID, 2009)</span>
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Adequate for</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Produce with high respiration rates<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Equipment required</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Ice</span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Storage and package containers which are suited for icing applications has to remain stable if being wet, such as waxed fibreboard cartons, wooden wire-bound creates, baskets, hampers and perforated plastic liners<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
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<u>'''Top icing''':</u> crushed ice is applied on the produce either manually or mechanically<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref><br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Adequate for</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Brokkoli, green onions, leafy greens, brussel sprouts, leeks, cantalpupes, parsley, carrots, peas, chinese cabbage<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
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<u>'''Liquid icing''':</u> ice and water mix is injected through vents or handholds into packages. This is done without opening packages and without removing them from pallets<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref><br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Advantages:</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Can be used for small and large operations alike<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Challenges:</span>
| style="width: 636px;" | <div><span style="line-height: 20.4px;">Produce gets in contact with water increasing the threat of microbial development. Sanitation is crucial. <ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span><br/></div>
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<u>'''Individual package icing''':</u> crushed ice is added manually on top of the packaged produce<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref><br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 130px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Advantages</span>
| style="width: 635px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Very simple<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 130px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Challenges</span>
| style="width: 635px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">There is the danger of produce being cooled unevenly since ice is simply put on top of packages/cartons<ref name="Ice">Application of ice on every single package is labor intensive and slow and is therefore mainly applied to small operationsUnknown Object</ref></span>
|-
| style="width: 130px;" | <br/>
| style="width: 635px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Application of ice on every single package is labor intensive and slow and is therefore mainly applied to small operations</span><ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>
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<br/>

<u>'''Ice bottles''':</u> ice bottles wrapped&nbsp;are placed in between produce<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>. An example is [[Solar_Milk_Cooling_with_Insulated_Milk_Cans|Solar Milk Cooling with Insulated Milk Cans]]<br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 130px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Advantages</span>
| style="width: 635px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Produce has no direct contact with ice<ref name="Ice">Application of ice on every single package is labor intensive and slow and is therefore mainly applied to small operationsUnknown Object</ref></span>
|-
| style="width: 130px;" | <br/>
| style="width: 635px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Can be used during transport<ref name="Ice">Application of ice on every single package is labor intensive and slow and is therefore mainly applied to small operationsUnknown Object</ref></span>
|}

<br/>

[[Pre-cooling of Agricultural Products#toc|►Go to Top]]<br/>


== Vacuum Cooling<br/> ==

temperature is reduced by placing produce in a metal cylinder in which the atmospheric pressure is reduce which leads to evaporation and a cooling effect<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref>.<br/>

{| style="width: 100%;" border="1" cellspacing="1" cellpadding="1"
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Advantages</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Fast and uniform cooling method<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Challenges</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Costly for small scale enterprise</span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">High water loss which can be prevented by adding water during the cooling process<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Adequate for</span>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Produce having a high surface to volume ratio<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Produce which cannot get in contact with water and for which using air is difficult<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">For leafy vegetables<ref name="Agriculture Information Bank, 2009">Agriculture Information Bank (2009) Pre-cooling of Fruits and Vegetables. [Online] Available from: http://agriinfo.in/default.aspx?page=topic&superid=2&topicid=2048 [accessed 29th July 2014]</ref></span>
|-
| style="width: 129px;" | <br/>
| style="width: 636px;" | <span style="line-height: 20.4px; background-color: rgb(255, 255, 255);">Brussels sprouts, carrot, peas, cauliflower, snap beans, celery, spinach, chinese cabbage, sweet corn, leek, Swiss chard<ref name="FAO, 2009">FAO (2009) Horticultural Chain Management for Countries of Asia and the Pacific Region. [Online] Available from: http://www.fao.org/3/a-i0782e/</ref></span>
|}

<br/>

The table below offers and overview of the various pre-cooling methods described summarizing their cooling time, suitability for produce, cost and efficiency.<br/>

[[File:Comparison of pre-cooling methods.png|thumb|left|600px|Comparison of pre-cooling methods|alt=Comparison of pre-cooling methods.png]]<br/>

<br/>

[[Pre-cooling_of_Agricultural_Products#toc|►Go to Top]]<br/>


= Further Information<br/> =

*[[Cold Storage of Agricultural Products|Cold Storage of Agricultural Products]]
*[[Small-scale Cold Storage For Fruit and Vegetables in India|Small-scale Cold Storage For Fruit and Vegetables in India]]
*[[Portal:Water and Energy for Food|Water and Energy for Food (WE4F) portal on energypedia]]
*[[Solar_Milk_Cooling_with_Insulated_Milk_Cans|Solar Milk Cooling with Insulated Milk Cans]]<br/>

<br/>

[[Pre-cooling of Agricultural Products#toc|►Go to Top]]<br/>


= References<br/> =

<references /><br/>

[[Category:Storage]]
[[Category:Agriculture]]
[[Category:Powering_Agriculture]]