The relative importance of fungi in the breakdown of commercial samples of sulphited strawberries

Abstract

Abstract The incidence of strawberry spoilage fungi in commercal plantations and on commercially harvested fruit from three different strawberry growing areas (East Norfolk, Wisbech area, County Wexford) were studied in relation to breakdown of sulphited fruit from these areas. Botrytis cinerea and Mucor piriformis were present on fruit from most plantations in the three areas whereas Rhizopus species were more prevalent on fruit from the Wisbech area. A higher proportion of stored fruit from the Wisbech area was spoiled by the Rhizopus spp., especially R. sexualls , whereas M. piriformis predominated on fruit from East Norfolk and County Wexford. A greater proportion of the sulphited fruit from the Wisbech area showed softening and disintegration which coincided with both a higher incidence of R. sexualis and of sulphited liquors showing detectable pectolytic activity. Comparison of the effect of the pre‐harvest fungicides Elvaron, Mildothane and Daconil, showed a similar incidence of M. piriformis and Rhizopus spp. on the fruit and subsequently there were no consistent differences in the amount of breakdown of sulphited fruit from the different treatments. A delay in sulphiting after the fruit had been harvested, especially when fruit was held at 15°C, usually resulted in complete disintegration during subsequent storage. The importance of reducing the interval between harvesting and sulphiting to a minimum is discussed together with other factors which may reduce the incidence of breakdown of sulphited fruit.