Water temperature for hydrocooling field cucumbers in relation to chillinginjury during storage

The objective of this study was to test the hypothesis that water temperatu res less than the lowest recommended storage temperature (10 degrees C) for cucumbers could be used for hydrocooling without inducing chilling injury or negatively affecting storage life. Field cucumbers were hydrocooled with water at 1.5, 3.5, 6, 8 or 10.5 degrees C until the internal cucumber temp erature reached 12 degrees C, or hydrocooled with water at 1.5 degrees C un til the internal cucumber temperature reached 1.7, 8 or 12 degrees C. Cucum ber temperature at harvest was approximate to 20 degrees C and the storage temperature was 12 degrees C. Little or no visual symptoms of chilling inju ry were observed after 10-12 days of storage. However, chlorophyll fluoresc ence measurements indicated some chilling stress at the membrane level in c ucumbers hydrocooled with water at temperatures below 6 degrees C and in cu cumbers hydrocooled with water at 1.5 degrees C until the internal product temperature was 1.7 degrees C, as indicated by lower F-v/F-m values. Approx imately one third of the cucumbers from all hydrocooling treatments develop ed rot. There were no significant differences in % marketable cucumbers or in % mass loss after 10 or 12 days of storage. These results suggest that c ucumbers could be hydrocooled using water at temperatures below the recomme nded storage temperature of 10 degrees C. However, it is not recommended to use water below 6 degrees C or to cool the cucumbers below this temperatur e, due to increased risk of chilling injury as indicated by the chlorophyll fluorescence measurements. (C) 2000 Elsevier Science B.V. All rights reser ved.