Temperature controlled transport as a solution
Temperature controlled transport as a solution16.01.2019 | By web3d_coldtruck
The most efficient way to postpone post-harvest loss and decrease decay is to maintain an adequate temperature throughout the storage and transportation period from harvest to market.
The controlled temperature transport can be divided into 2 main categories:
- Deep freeze temperature transport & storage (frozen)
- Chilled temperature transport & storage (fresh & perishable)
As a whole, one can state that frozen goods obtain a shelf life of weeks / months while the chilled and perishable goods shelf life is measured in days /hours.
Some of the goods are so sensitive, meaning they require air freight rather than storage, trucking or sea freight, in order to ensure their quality remains optimal within the consumption time period.
High level temperature-controlled transport requires professionalism, and a great understanding of the products themselves, the required (available) infrastructure, and the market requirements – its specifications and unique attributes.
Perishable goods are usually organic products such as processed food, dairy products, eggs, flowers, fruits & vegetables. These are usually maintained in chilled conditions and temperatures between 4-8 degrees Celsius (39.2 – 46.6F).
For example, apples are usually (depending on the variety) transported and stored at a temperature of zero degrees Celsius (32F) with minor ventilation for the vaporization of Ethylene, a bi product of the apple which is emitted once the apples have been harvested. The shelf life of an apple could be extended from 90 to 240 days depending on the conditions in which they are stored and transported.
Mango on the other hand, due to its sensitivity to low temperatures (cold frost symptoms) will have to be stored and transported at 12-14 degrees Celsius (53.6-57.2F), under which the shelf life can be optimized to a maximum of 14-21 days (mangos have high sensitivity to Ethylene exposure and therefore require even stronger ventilation).
Examples of the ramifications caused by incorrect temperature settings include, pears (which suffer from fungus before they are loaded for transport) which will consequently rot and be deemed worthless. Apples that have been exposed to freezing temperatures, as a result of incorrect settings could, in the best case, be used in animal feed, or the worst case, destroyed. Flowers and various other fresh produce, such as berries, spoil without adequate temperature control and are then worthless to the seller. In each case this can cause a major economic burden to the seller.
Other products, such as meat, fish, poultry, sea food, ice cream, juice & juice concentrates, are a separate sector which are usually maintained and transported in freezing temperatures (anywhere from zero to minus 20 degrees Celsius (32 to -4 F). Fish, for example, which are generally stored and transported at zero degrees Celsius will prolong the shelf life 5 times more than fish which are stored at 10 degrees Celsius.
Examining the products even further brings us to a variance among the commodities themselves depending on harvest methods and processes.
While some fish, seafood, and meat products are transported at a deep freezing temperature of minus 18 degrees Celsius (-0.4F), they can also be freshly moved (usually by air freight for immediate consumption) at non frozen temperatures of +4 degrees Celsius.
If we enter an even more specific categorization among the different fish and their geographic origins, fish of European origins, are being loaded from the sea with nets directly onto the fishing ships, where they are handled and immediately frozen for preservation. In comparison fish of East and West African origins, where the necessary facilities to adequately preserve the fish and decrease temperatures are not as developed causing a gap in product quality. The fish of East and West African origin are exposed to inferior transportation services which can hinder the condition of the fish. This creates the necessity for these fish to be double-checked in health and food labs to ensure the well-being of the intended consumer.
As one can see, the differences are vast, and being knowledgeable about the specific requirements and sensitivities of each product /species, will immensely influence the business model and the required facilities.
Products such as chemicals, medicines, and other biological products, especially the ones that are temperature sensitive (warm or cold), require preservation and temperature control, and at times humidity control, air isolation or even light isolation.
The handling of pharmaceuticals requires an entirely different set of facilities and processes which varies from drug to drug. These are strict temperature and transportation necessities, which if are not properly monitored and strictly adhered to, can easily be rejected by the receiver, depending on the variance of temperature and the sensitivity of the drug. A potential oversight can at times be hazardous if not maintained within the required range.
Pre cooling – a desired, although not always possible, preparation prior to stuffing the cargo into the box. The products and cooling boxes, prior to the stuffing process, are supposed to be calibrated (temperature wise). This allows the cooling box to preserves the temperature of the goods, rather than adjusts them to the desired temperature which they need to be transported at. These factors certainly influence the shelf life and sustainability of the products, especially for perishable goods with high sensitivity.
Cold chain throughout – maintaining of the ideal temperature for the product will ensure that no needless damages are incurred and that the product will be preserved to its maximal shelf life capacity.
Humidity – for certain products, such as coffee beans, cocoa beans, nuts and dried fruits, herbs & spices, roots, bulbs & onions, and others, the humidity preservation factor can be of great influence on the product sustainability and shelf life, considering a rather high humidity factor for longer preservation. At the same time, measures need to be taken to ensure that there is no needless extensive humidity within the box as this may create decay and/or rot. Each and every product obtains specifications for the ideal combination of temperature and humidity in order to prolong its’ shelf life.
Assuming relative humidity factors (combined with the original temperature of the product and the preset temperature of the box), will better control the accumulation of water drops in the coldest area of the storage facility. If the cooling coils will be colder than the product itself, it will create a dry area surrounding the fruit / vegetable, especially if the product was pre cooled according to specification prior to stuffing. These are all means to control the temperature of the cargo relative to the box, extend the shelf life, and determine to desired conditions for the specific product.
At the same time, if the goods were pre cooled beyond the desired temperature, while the box temperature is higher than the products temperature, the saturated water will generate visual humidity on the product itself, the packaging will get wet and the spoilage process will be expedited. The same principle applies to goods that are taken out of the storage/ transport box and exposed to non-adapted temperature, humidity and atmosphere.
For frozen goods, such as poultry, meat, fish, juices, juice concentrates and others, the pre freeze, and the preservation of the temperature at a safety spectrum in order to ensure goods are not even close to defrosting, is critical to the postponing the decay of these products, which actually start immediately as the animal’s life is terminated. Proteins start dissolving immediately, and fat structures start to leaven.
Fish with a higher fat content, such as haring (and similar), require more rigorous guidelines with regards to the pre cooling and freeze chain maintenance. Temperatures of pre freezing, depending on the fish’ and its fat levels, can vary from a recommended minus 18 degrees Celsius (-0.4F), down to a level of minus 30 degrees Celsius (-22F), despite the fact that the majority of the fish will be transported at minus 21 degrees Celsius (-5.8F). Naturally, any inadequate transport or storage (anything over minus 18 degrees Celsius) will decrease the preservation of the product, and may, in some cases, cause illness and/or be hazardous to consumers.
To further illustrate the consequences of non-tailored temperature prior to stuffing goods into the container (be it a truck box or reefer container) – if the produce’s temperature is expected to be decreased mainly by the cooling engine of the storage facility, the average variance of temperatures is calculated at 1-1.5 degrees Celsius per day when a container is stuffed with close to 25 tons of goods which are closely stacked and obtain isolation materials for preserving the product.