Controlled atmosphere is a technology based on variations of the parameters relative to atmospheric composition inside refrigerated/cold-storage rooms, consisting mainly in lowering the oxygen content and surveying the carbon dioxide value during the entire storage period of fresh produce.
Both technologies foresee a variation of the parameters relative to the atmospheric composition, but for modified atmosphere continuous monitoring during storage is no longer used (for example “bagged” products, cut-fresh etc ) whereas in controlled atmosphere continuous and constant monitoring of the gaseous composition is carried out using customized analysis systems and, if necessary, correction of the values can be made.
No. Controlled atmosphere is to be considered “clean” technology, and absolutely does not foresee the use of chemicals, and it is for this same reason that it is considered one of the safest and most reliable technologies with regards to human health .
Particularly, in the storage of biological products, a sector that has grown considerably over the last few years, this is the only available storage method.
The list of products that can benefit from being stored under controlled atmosphere is long. The main products are: apples, pears, kiwifruit, plums, blueberries, strawberries, tomatoes, mango ,avocado, pineapple, banana ,citrus fruits etc.
The possibility of controlled atmosphere application is linked to a number of physiological and anatomical characteristics ( intrinsic factors) and the sensitivity to certain external factors (extrinsic factors). Also ,within each species the behaviour of the various cultivars often differs according to the modifications sustained from factors of interference
It is therefore, unquestionable that the application of controlled atmosphere does not improve the quality of the product, but conserves the characteristics :only products with the best qualitative characteristics are suitable for storage using this technology.
Atmospheric air is composed of 20,8% oxygen, 78% nitrogen and about 0,03%carbon dioxide. The principle of controlled atmosphere is based upon the variation of this composition with the aim of slowing down ,as much as possible, the fruits’ respiration rate and relative maturity.
The main prerogative is the absolute impermeability/tightness of the storage room, therefore, during the construction phase it is necessary to provide all the necessary solutions to avoid gaseous exchanges with the outside environment once the store is destined for CA storage. In particular, the floor must be properly prepared , all refrigeration panel joints must be sealed, a suitable CA door installed, a siphon for the de-frost water discharge from the refrigeration plant must be installed, gas tightness of all passages and piping must be carried out and to complete the work the final gas-tightness test on termination of the running tests.
Ethylene is a hormone naturally produced by fruit , able to promote and accelerate maturity, with the effect of softening the pulp and de-greening the chlorophyll. Ethylene removal is often useful, especially for the more sensitive cultivars, (for example vegetables, kiwifruit, tropical fruits etc).
Ethylene may be removed by adsorbers using potassium permanganate or by catalytic converters even within existing cold stores, in fact, impermeabilized panels are not necessary .
Kiwifruit produces low levels of ethylene, but is also very sensitive to this hormone. For this reason it is important that the quantity of ethylene in the air does not exceed 0.02 ppm, above this level rapid maturation and deterioration of the fruits will occur . And for the same reason there are strong warnings against storing kiwifruit with other fruit/vegetable products.
Ethylene is difficult to detect at such low levels, and the most valid and precise system in use at this moment still remains gas chromatography.
During the storage period, fruit yields humidity to the environment. More humid the environment ,lesser humidity the fruit will surrender including relative weight loss. For this reason it is important to guarantee high relative humidity (RH) inside the storage room ,essentially by means of a well designed refrigeration plant (which avoids excessive condensation on the evaporator fins) and secondly through implementation of humidifiers that increase the RH value
ULO means Ultra Low Oxygen, an acronym introduced during the 80’s that indicates storage techniques using oxygen levels lower than 1,5% inside the store rooms/cells (nowadays the tendency is to maintain the value around 1%)
ULO is applied to guarantee even more restricted conditions with respect to traditional CA, with the aim of maintaining the qualitative characteristics of a product even longer.
It is mainly applied during the storage of apples.
ILOS means Initial Low Oxygen Stress and is based on the lowering of oxygen to extreme limits, around 0,5% inside the cell, for a brief period (+/-15 days) with the aim of avoiding the scald that some varieties of apples suffer during long-term storage, as well as maintaining optimal qualitative characteristics.
Swinglos technology represents the latest frontier in CA storage. The system is based on the principles of dynamic CA (DCA), according to which a constant and fixed value for the duration of storage is no longer foreseen, instead variable values (henceforth dynamic) are used. (LINK).
In other words the gaseous values undergo variations during the storage period according to the reply from the fruit itself ,especially the pulp, through application of repeated oxygen stress.
It is important to know what goes on inside the fruit pulp under such conditions to prevent and avoid the formation of alcohol in apples, which would render the product inedible. To this purpose, the only safe and applicable method is connected to alcohol analysis, easily detectable using an enzymic/enzymatic analyser
Certain cv are harvested early with respect to their full maturity, to allow them to be transported and handled (bananas for example). In such cases maturation is carried out during storage, using ethylene. Fruit Control Equipments markets/has a system which supervises automatic emission of the gaseous maturation mixture.
Controlled atmosphere is applied in numerous other situations as well as fresh produce storage. For example in the disinfestations sector, this method may be employed for the storage of various products such as seeds (wheat, rice, coffee ,pulses etc) nuts (walnuts, peanuts etc) dried foodstuffs (teas, herbs etc) and even beverages (oils, wine, juices etc.)
Yes, controlled atmosphere in its’ wider term is used in other fields such as the transformation of plastics, the archiving and disinfestation of works of art, the neutralization/sterilization of premises and storage areas using technical gases and many other applications
Fruit Control Equipments’ staff, with over 50 years of global experience in this field, is able to give advice on the products to be stored in controlled atmosphere, suggesting the best technology currently available for each product.
We also design, build and market all the equipment and accessories relative to the application connected to long-term storage of fresh horticultural produce and various other applications, also for non-foodstuffs.
Fruit Control Equipments, a leader and standard bearer of “made in Italy” around the world/worldwide leader and standard bearer of “Made in Italy”, produces entirely in Italy.
The production site is in Locate Triulzi, in the milanese outer-metropolitan area, within easy reach of three international airports.
The technical, commercial and administrative offices are housed in the same premises.
Fruit Control Equipments’ customers are spread worldwide in over 45 nations . The company is able to manage all problems related to controlled atmosphere application with a staff composed of agronomists, technicians and engineers and can give complete service, from the design stage up to plant supervision.
Our collaboration with leading national and international research institutes has always been very close, in order to enable us to study and apply innovative technologies in the field of fresh horticultural produce storage, as demonstrated by various international publications.
There are also a wide number of research institutes worldwide with FCE signature plants
Controlled atmosphere is applied to extend the storage life of fruits and vegetables. Most of them can be stored considerably for more time compared with normal 0° cold store. In fact CA reduce drastically metabolism and respiration of the fruits.
In this list there are some products which can take advantage from CA storage
Regarding the time of storage in CA/ULO conditions a lot depends from the initial conditions of fruits (ripening level, presence of physiological disorders, etc.) and from other components during storage (quality of refrigeration system, level of humidity, etc).
All the parameters should be managed properly in order to maintain the initial quality during storage. Just to give some example it’s possible to store some cv. of pears and apples even for 12 months, cherries up to 90 days, cauliflowers 70 days and mangoes up to 50 days with the proper technology.
The cost of a CA plant is very variable, being necessary to know which is the fruits or vegetables to be store, because each product required different parameters in terms of oxygen, carbon dioxide, ethylene and humidity.