Advances in DCA, Dynamic Controlled Atmosphere, to control apple and pear scald

Since the early 1960s, DPA has been the primary method to control superficial scald, a major disorder in stored apples and pears. In June, 2012 the EU removed diphenylamine (DPA) from its list of approved pesticides. This presentation is a review of the research and development of low O2 ? based ?DCA technologies as a commercial replacement for DPA. Beginning with experiments that began over 110 years ago in 1903, research showed that superficial scald in apples and pears is entirely prevented by storage in very low O2 concentrations, i.e., between 0% and 1% O2. However, some of this work indicated that low O2 fails to control or sometimes increases superficial scald. In addition, there was no reliable method to measure the lowest acceptable concentration and some research suggested that if the O2 is too low for too long, fruit damage occurs. Lastly, controlled - atmosphere (CA) room construction and control was not always sufficient to maintain adequate low O2 conditions (e.g. <1%). Therefore, the use of CA to control superficial scald was not embraced by industry. However, in the 1980s as CA room construction and gas control became more advanced, industry began testing low O2 methods to replace DPA, e.g. 0.7% O2 on ?Delicious? apple in British Columbia, Canada, initial low O2 stress (ILOS) (various countries) and ILOS+ (ILOS with ethanol monitoring). The advent of DCA -Chlorophyll Fluorescence (DCA - CF) technology in 2001, which determines the lowest acceptable level of O2 in storage, removed the fear of fermentation and low O2 damage and gave the fruit industry more confidence to use DCA (rather than DPA), for controlling superficial scald. The apple industry of South Tyrol was changing to CA - based technologies to control superficial scald; in this Italian region the DPA has not been used for 2 years. The most recent development is a combination of DCA - CF with anti -ethylene compounds, e.g. 1 - methylcyclopropene (1-MCP) or aminoethoxyvinylglycine (AVG), to add extra scald prevention during shelf - life for very superficial scald - prone apples. ? Original title, complete list of authors, and sources:THE SUCCESSFUL ADOPTION OF DYNAMIC CONTROLLED - ATMOSPHERE (DCA) STORAGE AS A REPLACEMENT FOR DIPHENYLAMINE (DPA), THE CHEMICAL USED FOR CONTROL OF ?SUPERFICIAL SCALDPrange, R.K.1(*), Zanella, A.2, Delong, J.M.3 and Wright, A.H.4 rkprange@gmail.com1 Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3 Canada2 Laimburg Research Centre for Agriculture and Forestry, Laimburg 6 Pfatten (Vadena), 39040 Auer (Ora), BZ, Italy3 Agriculture and Agri - Food Canada, Atlantic Food and Horticulture Research Centre, Kentville, NS, B4N 1J5 Canada4 Laval University, Quebec City, QC G1V 0A6 CanadaCA MA 2013, XI International Controlled & Modified Atmosphere Research Conference Trani (Italy), 3-7 June 2013 The picture, by Isolcell, summarizes the DCA concept ? ?