Fruit and vegetables - Principles and techniques of the controlled atmosphere method of storage
other information
Release date:2009-03-28
drafter:Feng Jianhua, Xu Xinming, Jiang Guichuan, Ji Xiangyang, Jia Lianwen, Yu Wangqing
Drafting unit:All-China Federation of Supply and Marketing Cooperatives Jinan Fruit Research Institute, Shandong Agricultural Management Cadre College
Focal point unit:All-China Federation of Supply and Marketing Cooperatives Jinan Fruit Research Institute
Proposing unit:All-China Federation of Supply and Marketing Cooperatives
Publishing department:General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of China
competent authority:All-China Federation of Supply and Marketing Cooperatives
Some standard content:
ICS 67.080.10
National Standard of the People's Republic of China
GB/T23244—2009
Technical Specification for Controlled Atmosphere Storage of Fruits and Vegetables
Fruit and vegetables--Principles and techniques of the controlled atmosphere method ofstorage
(ISO6949.1988,NEQ)
2009-03-28 Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of China
2009-08-01 Implementation
People's Republic of China
National Standard
Technical Specification for Controlled Atmosphere Storage
Fruits and Vegetables
GB/T23244-—2009
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Format 880×1230
First edition in June 2009
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Word count 8,000 words
First printing in June 2009
Book number: 155066·1-37286
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GB/T23244—2009
Technical Specification for Controlled Atmosphere Storage" (English version). This standard adopts ISO6949:1988 "Fruits and Vegetables" in a non-equivalent manner. Compared with ISO6949:1988, this standard has made the following modifications: the foreword has been deleted;
some contents in the scope of application have been modified and adjusted; some gas indicators in the gas conditioning type have been modified; - the contents of the gas composition adjustment chapter have been redrafted; - the contents of the ethylene removal clause have been added; - the contents of the humidity adjustment clause have been added; - the contents of the safety management chapter have been added;
the informative Appendix A in the original standard has been deleted. This standard was proposed by the All-China Federation of Supply and Marketing Cooperatives. This standard is under the jurisdiction of the Jinan Fruit Research Institute of the All-China Federation of Supply and Marketing Cooperatives. The drafting units of this standard are: Jinan Fruit Research Institute of the All-China Federation of Supply and Marketing Cooperatives, and Shandong Agricultural Management Institute. The main drafters of this standard are: Feng Jianhua, Xu Xinming, Jiang Guichuan, Ji Xiangyang, Jia Lianwen, and Yu Wangqing. 1 Scope
Technical Specifications for Controlled Atmosphere Storage
Fruits and Vegetables
This standard specifies the procedures and techniques for controlled atmosphere storage of fruits and vegetables. GB/T23244—2009
This standard applies to all kinds of fruits and vegetables, especially to the controlled atmosphere storage of fruits and vegetables with respiratory climacteric type, such as apples, pears, bananas and garlic. 2 Types of Controlled Atmosphere Storage
Controlled atmosphere storage can be divided into two types.
2.1 Type I
Reduce the oxygen content and increase the carbon dioxide content, but the sum of oxygen and carbon dioxide content is 21% (volume fraction). 2.2 Type II
Reduce the oxygen content and increase the carbon dioxide content, and the sum of oxygen and carbon dioxide content is less than 21% (volume fraction). The gas composition can be adjusted according to the product type and taking into account the following factors: the sensitivity of fruits and vegetables to high carbon dioxide concentration and low oxygen; maturity;
storage time.
3 Controlled atmosphere storage methods
There are three main controlled atmosphere storage methods:
a) The product is stored in a specially equipped storage room or device, and a gas combination different from the normal gas composition is prepared with special equipment, and the concentration of oxygen and carbon dioxide is kept within a limited range; the product is stored in a bag or large tent inlaid with a silicone rubber membrane with a good air permeability ratio; b)
The stored product is subjected to short-term high carbon dioxide treatment. 4 Controlled atmosphere storage warehouse
4.1 Capacity
The storage capacity of the controlled atmosphere warehouse generally ranges from tens of tons to thousands of tons. 4.2 Air tightness
The controlled atmosphere storage room should achieve a certain degree of air tightness to maintain the stability of the gas composition in the warehouse. 4.2.1 Minimum air density
The minimum air density of the controlled atmosphere storage room should meet the most stringent operating conditions. 4.2.2 Construction
The building structure of the gas conditioning storage should have good thermal insulation, airtightness and safety. The walls, floors and ceilings of the assembled gas conditioning storage should be made of sandwich color steel plates, aluminum plates, glass fiber reinforced polyester resins, epoxy resins or amide resins. The brick-concrete structure gas conditioning storage should have the function of blocking water vapor and airtightness, and the foundation should be stable without settlement, deformation, etc. The storage room is sealed with an insulated door, and an observation window and a small door to enter the storage room should be installed on the door. An inspection window is set in the upper part of the storage room, and its position should be higher than the stacking height of the stored products, so that it is convenient to enter the upper part of the stored products through the window to check the status of the stored products, evaporators and refrigeration equipment. Airtight materials should have the following characteristics: 1. Airtight;
Do not release odor or toxic substances;
-Waterproof and antibacterial;
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GB/T23244-2009
Easy to install and maintain;
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-Fireproof;
-Maintain its characteristics when the temperature, relative humidity and pressure in the storage room change. The airtightness of the storage room should be improved in the following cases: low storage temperature;
-Products in the storage warehouse are often not fully filled;
-Storage products with particularly low respiration rates. 4.3 Airtightness guarantee measures
Due to the operation of fans, refrigeration equipment, air conditioning equipment and fluctuations in external pressure, a pressure difference will be formed inside and outside the storage room. A sudden drop in pressure in the storage room may cause the airtight layer to detach from the wall and ceiling, thereby destroying the airtightness of the storage room. Therefore, it is recommended to take the following safeguard measures:
- Each gas-controlled storage room should be equipped with a pressure balance valve and a pressure balance bag. The pressure balance bag should have good strength and airtightness, and its volume should be 5%-7% of the remaining space in the storage room; the refrigeration, air extraction, air conditioning, circuit and other pipelines passing through the airtight layer should be carefully sealed:- The airtight door of the gas-controlled storage room should be sealed after the temperature drops to a suitable storage temperature and stabilizes, and the oxygen concentration drops to a suitable level; the pressure fluctuation value of the gas-controlled storage room should be less than 9.8Pa (1mm water column). 4.4 Airtightness detection
The airtightness of the storage room should be checked before the first use and every year thereafter. The methods 4.4.1 and 4.4.2 can be used for detection.
4.4.1 Convection method to measure the pressure change of the empty warehouse Empty warehouse detection at room temperature when the fan is not running. When the convection method is used to measure the airtightness of the storage room with a balance bag, the balance bag valve should be closed first. There are two main methods: a) Seal the door and use an air pump to increase the pressure from the initial set gauge pressure of 98.1Pa (10mm water column). The pressure value reached after 30 minutes is used to evaluate the air tightness:
Pressure increase of 33.3Pa (3.4mm water column) or more is excellent; a pressure increase of 9.8Pa~33.3Pa (1mm~3.4mm water column) is good; a pressure increase of less than 9.8Pa (1mm water column) is poor. b) Calculate the time required to reduce the initial set pressure in the storage room by half. At a constant temperature, this time exceeds 10min~12min, and the air tightness of the storage room is qualified. 4.4.2 Determination of changes in carbon dioxide and oxygen content in empty warehouses by diffusion method This method is particularly suitable for storage rooms with balance bags that cannot be measured by convection method. Determine the carbon dioxide content in the storage room, and then continuously measure the carbon dioxide and oxygen content, and determine the air tightness status based on their changes. For example: the carbon dioxide content in the storage room is 15% (volume fraction) and the oxygen content is 6% (volume fraction). If the carbon dioxide content decreases by no more than 1% (volume fraction) and the oxygen content increases by no more than 0.25% (volume fraction) after 24 hours with the fan running, the air tightness is considered adequate. 4.5 Detection of air leakage faults
Seal the door of the storage room, and increase or decrease the pressure in the storage room by 98.1Pa (10mm water column) without turning on the fan. Observe the following conditions inside or outside the storage room to determine whether there is a leak: - The steam mist generated in the storage room flows in a certain direction; - There is a whistle sound of air entering and leaving the storage room; - When applying soapy water to the suspicious area, bubbles are generated; ... - A burning candle is placed in a suspicious place, and the flow of air makes the flame longer. 2
4.6 Maintenance
GB/T23244—2009
Storage rooms with unqualified air tightness should be repaired before the products are stored. After the maintenance is completed, the air tightness of the storage room should be retested. 5 Regulation of temperature, humidity and gas composition
5.1 Temperature regulation
Products should be put into storage for pre-cooling immediately after harvesting, and the storage temperature should be lowered to a suitable storage temperature and kept stable. The daily storage volume should meet the design requirements of the gas-controlled storage.
5.2 Gas composition regulation
In addition to requiring the temperature and relative humidity to be kept within the optimal range, the oxygen and carbon dioxide content should be adjusted to the required range, and ethylene should be removed.
Gas-controlled storage requires that fruits and vegetables be harvested in time, put into storage immediately after harvesting, filled as soon as possible, and gas adjusted in time so that fruits and vegetables can enter a suitable gas-controlled state as soon as possible, generally not exceeding 7 days.
5.2.1 Regulation of oxygen content
In the atmosphere storage room, the oxygen content in the atmosphere is reduced to 21% (volume fraction) by relying on the respiration of the stored products or by using special equipment.
5.2.1.1 Reducing oxygen by relying on the respiration of fruits and vegetables The respiration process of fruits and vegetables consumes oxygen and produces carbon dioxide, water and heat. The speed of oxygen content reduction depends on the respiration rate of the stored products, the size of the storage room, the storage volume, etc. The door should not be opened during storage, otherwise it will take a long time to meet the requirements, and it will also cause fluctuations in gas composition, which is not conducive to product storage. 5.2.1.2 Application of oxygen reduction equipment to reduce oxygen
The application of oxygen reduction equipment can reduce the oxygen content to the required level within 2d to 3d. Currently, the commonly used oxygen reduction equipment includes: carbon molecular sieve nitrogen generator, hollow fiber membrane nitrogen generator, etc.
During the process of nitrogen filling and oxygen reduction, the valve of the pressure balance airbag of the gas conditioning storage should be closed, and the gas conditioning storage should not be completely closed to avoid large pressure fluctuations that damage the pressure balance airbag and the gas conditioning storage body. A certain gap should be left at the observation window, and it should be completely sealed after shutdown, and the pressure balance airbag valve should be opened.
5.2.2 Regulation of carbon dioxide content
The breathing of the stored products causes carbon dioxide to accumulate in the storage room. Carbon dioxide removal equipment should be used to reduce the carbon dioxide content to a reasonable level.
5.2.3 Removal of ethylene
The ethylene-containing gas in the storage is removed by an ethylene remover, and then sent to the gas conditioning storage through a closed-loop circulation system. When an ethylene remover based on the principle of heating and catalytic decomposition of ethylene is used, in order to reduce the impact of the temperature of the incoming gas on the stored products, the location of the air inlet should avoid being directly facing the stored products, or the stacking of the stored products should avoid the location of the air inlet. 5.3 Humidity adjustment
Measure the relative humidity regularly and adjust the relative humidity in the warehouse in time according to the changes. Common humidification devices include: water mixing humidifier, ultrasonic humidifier and centrifugal atomization humidifier. When these humidifiers are used at temperatures above 0℃, they can be used normally according to the instructions; when used at temperatures below 0℃, the number of humidifications should be increased, the time of each humidification should be reduced, and the water in the humidifier should be emptied at the end of each humidification to avoid freezing of the water in the humidifier. 6 Maintenance of ideal gas combination
After reaching the required oxygen and carbon dioxide indicators, they should be kept stable. The method for maintaining the adjusted gas combination is as follows: nitrogen or air is regularly input into the type I environment to replace the gas in the original storage environment; the air tightness should reach 300Pa and the half-pressure reduction time should not be less than 20min~30min. - Use removal equipment to regularly remove carbon dioxide in the type II environment, and input fresh air to supplement the oxygen content. KAONKACa
GB/T23244—2009
7 Inspection and management during storage
In the first 20 days, check the storage control parameters (including temperature, relative humidity and gas composition) twice a day, and then check them once a day after 20 days, and read the data directly or record them with instruments.
Check the quality of stored products regularly and deal with problems in time. 8 Outbound management at the end of controlled atmosphere storage
When the controlled atmosphere storage is over, it is best to ship all the fruits and vegetables out of the warehouse at one time or in batches within a short period of time. 9 Safety management
9.1 Set up low oxygen hazard warning signs at the entrance and other suitable locations of the storage room. 9.2 Operate the facilities and equipment of the controlled atmosphere warehouse in strict accordance with the management and operating procedures. 9.3 It is strictly forbidden for personnel to enter the storage room in the atmosphere-controlled state without wearing oxygen protective masks. When it is necessary to enter for a short time for operation or inspection, safety measures such as intact oxygen protective masks should be in place. At least two people should work together, one wearing a safety protective mask with sufficient oxygen to enter the warehouse for operation, and the other person should monitor outside the warehouse, and the activities of the personnel in the warehouse must be within the visual range of the personnel outside the warehouse. 9.4 At the end of the atmosphere-controlled storage, the door of the storage room should be opened first, and the fan should be turned on for 1h2h. When the excessive carbon dioxide is eliminated and the oxygen content is close to the atmospheric level, the staff can enter without wearing a safety protective mask. Copyright exclusive infringement must be investigated
Book number: 155066·1-37286
GB/T23244-2009
Pricing:3 Humidity adjustment
Measure the relative humidity regularly and adjust the relative humidity in the warehouse in time according to the changes. Common humidification devices include: water mixing humidifier, ultrasonic humidifier and centrifugal atomization humidifier. When these humidifiers are used at temperatures above 0°C, they can be used normally according to the instructions; when used at temperatures below 0°C, the number of humidifications should be increased, the time of each humidification should be reduced, and the water in the humidifier should be emptied at the end of each humidification to avoid freezing of the water in the humidifier. 6 Maintenance of ideal gas combination
After reaching the required oxygen and carbon dioxide indicators, they should be kept stable. The method for maintaining the adjusted gas combination is as follows: nitrogen or air is regularly input into the type I environment to replace the gas in the original storage environment; the air tightness should reach 300Pa and the half-pressure reduction time should not be less than 20min~30min. - Use removal equipment to regularly remove carbon dioxide in the type II environment, and input fresh air to supplement the oxygen content. KAONKACa
GB/T23244—2009
7 Inspection and management during storage
In the first 20 days, check the storage control parameters (including temperature, relative humidity and gas composition) twice a day, and then check them once a day after 20 days, and read the data directly or record them with instruments.
Check the quality of stored products regularly and deal with problems in time. 8 Outbound management at the end of controlled atmosphere storage
When the controlled atmosphere storage is over, it is best to ship all the fruits and vegetables out of the warehouse at one time or in batches within a short period of time. 9 Safety management
9.1 Set up low oxygen hazard warning signs at the entrance and other suitable locations of the storage room. 9.2 Operate the facilities and equipment of the controlled atmosphere warehouse in strict accordance with the management and operating procedures. 9.3 It is strictly forbidden for personnel to enter the storage room in the atmosphere-controlled state without wearing oxygen protective masks. When it is necessary to enter for a short time for operation or inspection, safety measures such as intact oxygen protective masks should be in place. At least two people should work together, one wearing a safety protective mask with sufficient oxygen to enter the warehouse for operation, and the other person should monitor outside the warehouse, and the activities of the personnel in the warehouse must be within the visual range of the personnel outside the warehouse. 9.4 At the end of the atmosphere-controlled storage, the door of the storage room should be opened first, and the fan should be turned on for 1h2h. When the excessive carbon dioxide is eliminated and the oxygen content is close to the atmospheric level, the staff can enter without wearing a safety protective mask. Copyright exclusive infringement must be investigated
Book number: 155066·1-37286
GB/T23244-2009
Pricing:3 Humidity adjustment
Measure the relative humidity regularly and adjust the relative humidity in the warehouse in time according to the changes. Common humidification devices include: water mixing humidifier, ultrasonic humidifier and centrifugal atomization humidifier. When these humidifiers are used at temperatures above 0°C, they can be used normally according to the instructions; when used at temperatures below 0°C, the number of humidifications should be increased, the time of each humidification should be reduced, and the water in the humidifier should be emptied at the end of each humidification to avoid freezing of the water in the humidifier. 6 Maintenance of ideal gas combination
After reaching the required oxygen and carbon dioxide indicators, they should be kept stable. The method for maintaining the adjusted gas combination is as follows: nitrogen or air is regularly input into the type I environment to replace the gas in the original storage environment; the air tightness should reach 300Pa and the half-pressure reduction time should not be less than 20min~30min. - Use removal equipment to regularly remove carbon dioxide in the type II environment, and input fresh air to supplement the oxygen content. KAONKACa
GB/T23244—2009
7 Inspection and management during storage
In the first 20 days, check the storage control parameters (including temperature, relative humidity and gas composition) twice a day, and then check them once a day after 20 days, and read the data directly or record them with instruments.
Check the quality of stored products regularly and deal with problems in time. 8 Outbound management at the end of controlled atmosphere storage
When the controlled atmosphere storage is over, it is best to ship all the fruits and vegetables out of the warehouse at one time or in batches within a short period of time. 9 Safety management
9.1 Set up low oxygen hazard warning signs at the entrance and other suitable locations of the storage room. 9.2 Operate the facilities and equipment of the controlled atmosphere warehouse in strict accordance with the management and operating procedures. 9.3 It is strictly forbidden for personnel to enter the storage room in the atmosphere-controlled state without wearing oxygen protective masks. When it is necessary to enter for a short time for operation or inspection, safety measures such as intact oxygen protective masks should be in place. At least two people should work together, one wearing a safety protective mask with sufficient oxygen to enter the warehouse for operation, and the other person should monitor outside the warehouse, and the activities of the personnel in the warehouse must be within the visual range of the personnel outside the warehouse. 9.4 At the end of the atmosphere-controlled storage, the door of the storage room should be opened first, and the fan should be turned on for 1h2h. When the excessive carbon dioxide is eliminated and the oxygen content is close to the atmospheric level, the staff can enter without wearing a safety protective mask. Copyright exclusive infringement must be investigated
Book number: 155066·1-37286
GB/T23244-2009
Pricing:
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