Determining suitable non-damaging treatments for post-harvest disinfestation of fruit fly in mango.
Grové T., Steyn W. P., Beer M. S. de
Author Affiliation: Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200, South Africa.
: 119-125
Abstract : Three fruit fly species are known to attack mangoes in South Africa. Countries such as Japan and the United States, which are climatically suitable for fruit fly establishment, impose quarantine restrictions against countries likely to carry new fruit fly species into their boundaries. In this study the effect of hot water immersion on fruit quality was tested to gather baseline information before the treatment is tested on a broader commercial basis. Eight different cultivars were used, namely Tommy Atkins, Irwin, Zill, Neldica, Kent, Keitt, Heidi and Sensation. All fruits were washed and immersed in water at a temperature of 46.1°C for four different time intervals namely 5 minutes, 30 minutes, 60 minutes and 90 minutes. The fruit were then allowed to cool for 24 hours and were stored for 28 days at 11°C. Afterwards fruit were allowed to ripen at 20°C for 4 days and then evaluated. The evaluation criteria included: (1) Skin colouration (2) Total soluble solids (3) Physiological disorders (4) Diseases (5) Lenticel damage and scalding (6) Pulp penetration pressure (7) Pulp colour (8) Taste. Tommy Atkins fruit were immersed in water at a temperature of 46.1°C for 90 minutes. Half of the fruit were placed directly into cold storage while the remaining fruit were placed into cold storage after 24 hours. Sensation fruit were immersed for 60 and 90 minutes in water at 46.1°C, 47.1°C, 48.1°C, 49.1°C and 50.1°C. Results indicated that most cultivars immersed in water at 46.1°C for 90 minutes and refrigerated after 24 hours were not damaged and suitable for exportation, whereas some cultivars showed unacceptable levels of lenticel damage. Tommy Atkins fruit which were refrigerated immediately after immersion displayed surface scald. Water temperatures of 48.1°C and higher affected the fruit.