From Our Archives - Cut Post - Harvest Pear Losses

40 YEARS AGOFG Mitchell, of the University of California in the US, discusses tests done on the cooling and warming of Bon Chretien pears in the state, and their affect on pear quality.

“In recent years, many changes have occurred in pear handling procedures in California. Small field lugs have been replaced by unitised pallet handling, individual handling of shipping containers has been replaced by unitised pallet handling, and maximum storage periods have been lengthening (now about two months for processing and three to five months for fresh market). These changes have caused cold storage operators to attempt fruit cooling under difficult conditions, and to store a greater volume of product. As these changes occurred, and as deterioration problems become more severe, there was a tendency to blame the difficulties on undefined changes in the fruit, on harvest maturity, or on other orchard or handling practices. It thus became imperative to make a careful study of the problems and the following findings resulted.

“Late-harvested fruit showed more breakdown than early or midseason fruit, and single-pick fruit showed more breakdown than two-pick fruit. However, fruit harvested at a firmness or slightly below the minimum allowed for processing (6,3kg) developed little breakdown, if promptly cooled and stored at a low temperature (-1°C). With proper temperature management, fruit harvested in late season showed no increase in watery breakdown incidence even after eight weeks’ cold storage.

COOLER

“Pears cooled within 24 hours of harvest then stored showed no increase in breakdown compared to fruit ripened immediately after harvest. Each additional day of cooling delay was roughly equal to one week harvest delay, both in incidence of fruit breakdown and in flesh firmness after storage. Thus a rapid cooling method must be employed, if the fruit is to be protected from deterioration.