ABSTRACT
CONTENTS 2.1 Introduction .......................................................................................................................... 1 2.2 CA Methods.......................................................................................................................... 18
2.2.1 Controlled Ventilation............................................................................................ 19 2.2.2 Conventional CA .................................................................................................... 19 2.2.3 Low O2 Storage and Ultralow O2 Storage .......................................................... 20 2.2.4 Rapid CA.................................................................................................................. 20 2.2.5 Initial Low O2 Stress............................................................................................... 21 2.2.6 Delayed CA.............................................................................................................. 22 2.2.7 Dynamic Control of CA or Dynamic Control System ...................................... 22 2.2.8 Low Ethylene........................................................................................................... 24 2.2.9 Low-Pressure Storage or Hypobaric Storage and Others................................. 25 2.2.10 Modified Atmosphere ............................................................................................ 26
2.3 Storage Facilities and Pallet Package Systems ‘‘Palistore’’............................................ 26 2.3.1 Rooms ....................................................................................................................... 26 2.3.2 Pressure Relief Valves ............................................................................................ 28 2.3.3 Expansion Bags ....................................................................................................... 29 2.3.4 Leakage Specifications............................................................................................ 30 2.3.5 MA and CA Pallet Bag Systems (MCA Pallet CA)............................................ 32
2.4 Establishment of Controlled Atmosphere........................................................................ 33 2.4.1 Oxygen (O2) Removal ............................................................................................ 33 2.4.2 Carbon Dioxide (CO2) Removal ........................................................................... 36 2.4.3 Ethylene (C2H4) Removal ...................................................................................... 38
2.5 Control of Storage Atmosphere......................................................................................... 39 2.5.1 Oxygen (O2) ............................................................................................................. 39 2.5.2 Carbon Dioxide (CO2)............................................................................................ 40 2.5.3 Ethylene (C2H4) ....................................................................................................... 40 2.5.4 Automation and Control Systems........................................................................ 40 2.5.5 Monitoring Produce Response and Adaptive Control...................................... 42
2.6 Safety Considerations.......................................................................................................... 44 2.7 Future Developments.......................................................................................................... 45 References...................................................................................................................................... 46
Controlled atmosphere (CA) storage using low oxygen (O2) levels and high carbon dioxide (CO2) levels in the storage atmosphere combined with refrigeration is probably the most successful technology introduced to the fruit and vegetable industry in the twentieth century. In particular, its implementation concerning apples revolutionized storage possibilities of this commodity. Even very early storage practices may have utilized modified atmosphere (MA) enriched with CO2 and depleted O2 levels to extend storage life of fruits, vegetables, cereals, and other commodities (Dilley, 2006). First research concerning CA storage began in the early 1800s in France (Dalrymple, 1999). Jacques Etienne Berard at the University of Montpellier in France observed that fruits did not ripen in an atmosphere depleted of O2 (Dalrymple, 1999). Other studies covered the effects of low levels of O2 and of high levels of CO2 on ripening and first attempts of Benjamin Nyce on CA storage followed in 1865 (Dilley, 2006). However, the basis for commercial application of CA was established by Kidd and West (1927, 1930, 1937, 1950) who investigated the effects of O2, CO2, and C2H4 (ethylene) on respiration and ripening in pome fruits and berries. Consequently, the first commercial CA storage facility was constructed in Kent, England, in 1929. Soon the success of apple storage employing the ‘‘gas storage’’ or CA technique started its worldwide expansion. Eaves (1934) was responsible for the fruit and vegetable storage program at the Experimental Farm in Kentville, Nova Scotia, Canada, and initiated construction of the first commercial CA storage in Canada. The first commercial CA storage facilities in South Africa were installed in the Elgin Valley near Cape Town in 1935 (Dilley, 2006; Graham, 2008). Research on CA storage prompted the further construction of CA storage facilities in New York state in 1940 (Smock, 1941). However, CA usage only became more common after 1950 as CA technology improved. Further developments during the 1990s and ongoing technical innovations are expanding its use worldwide (Prange et al., 2005b). Initially commercial CA storage was nearly exclusively applied to apples. This was
certainly related to its incomparable advantages to refrigeration only for this specific produce. In addition, CA storage offered a means to alleviate some storage disorders and diseases of apples. Although other disorders may be aggravated or induced by CA storage, in general its benefits prevail (Prange et al., 2006). However, research investigating applications for other commodities was pursued from the beginning and led to commercial use and recommended CA conditions for storage of other fruits, vegetables, fresh cut fruits, and vegetables as well as cut flowers and ornamentals (Brecht, 2006; Erkan and Wang, 2006; Kader, 2003; Kupferman, 2003; Saltveit, 2003a; USDA-ARS, 2004). Finally, specific applications of CA include insect control and disinfection (Mitcham et al., 2003).
