Steam treatment to prevent carrot decay during storage

Organically grown carrots (Daucus car ora L.) have a relatively short storage and shelf life, mainly because chemical measures cannot be implemented to control plant pathogens. Laboratory experiments demonstrated that steam treatments substantially reduced decay of stored organically grown carrots. Prior to being packaged, winter carrots were exposed to 3 s of steam. After 60 days of storage at: 0.5 degrees C plus an additional week at shelf conditions (20 degrees C), 2% of the carrots were decayed, as opposed to 23% in the nontreated control. When carrot was inoculated with the fungi Alternaria alternata, [(Fr:Fr.) Keissler] A. radicina (Meier) and Sclerotinia sclerotiorum [(Lib.) De Bary], percentages of decay, after similar periods of storage and shelf life, were 5% for steam-treated carrot and 65% for the nontreated control. In semi-commercial experiments carrots were treated with steam during the sorting process, and similar results were obtained. Higher decay was found in spring-grown carrots because of the presence of the bacterium Erwinia carotovora.sub. sp. carotovora. (C) 2000 Elsevier Science Ltd. All rights reserved.