An assessment of the decay hazard associated with hydrocooling strawberries.
Ferreira, M. D.; Bartz, J. A.; Sargent, S. A.; Brecht, J. K.;
Plant Disease Year: 1996 Vol: 80 Issue: 10 Pages: 1117-1122 Ref: 32 ref.
1996
บทคัดย่อ
The decay hazard associated with hydrocooling strawberries was related to whether they became inoculated with postharvest pathogens during the procedure. Storage of hydrocooled berries at warmer temp. or for longer periods than recommended allowed inoculation to be expressed into disease. Cooling strawberries by immersion hydrocooling did not consistently lead to increased postharvest decay when compared with conventional forced-air cooling in 2 separate trials. No differences in decay incidence were found in berries that were hydrocooled versus forced-air cooled and then stored for 7 days at 1 deg C plus 1 day at 20 deg . With a 15-day storage regime (14 days at less than or equal to 7 deg plus 1 day at 20 deg ), hydrocooled fruit developed less decay than forced-air-cooled fruit in 1 trial but more decay in a second. Wrapping baskets of cooled berries with plastic film promoted disease development and slowed the moisture loss from both hydrocooled and forced-air-cooled berries. The wrap did no
t promote disease more when applied to wet, hydrocooled berries compared with dry, forced-air-cooled berries. Residual moisture left on the berries by the hydrocool treatment did not predispose the fruit to postharvest decay. In contrast, wounds and abrasions on hydrocooled fruit were temporarily water soaked and berries typically increased in weight as they were hydrocooled. Berries cooled in water containing spores of Botrytis cinerea or Rhizopus stolonifer developed nearly 100% decay incidence during a storage regime that favoured specific development of grey mould (11 days at 7 deg ) or Rhizopus rot (2 days at 24 deg ). Chlorinating the hydrocooler water (120 mg of free chlorine/litre at pH 6.5) before adding the berries and spores reduced the incidence of grey mould to 43%; in contrast, berries hydrocooled in clean water developed 61% grey mould. Chlorination of the clean water led to significant reductions in the incidence of grey mould (44%) but did not affect the incidence of Rhizopus rot. The hydroc
ool method for cooling strawberries with the addition of proper chlorination has promise as a rapid method for cooling and cleaning berries and reducing grey mould inoculum on berry surfaces.