3. Handling
A) Packing house operations: The packing house operations include the following steps:-
- Dumping / collection
- Pre-sorting
- Washing / Cleaning
- Sizing / Grading
- Bunching / Wrapping
- Postharvest Treatments
- Packing
- Cooling
It is important to minimize mechanical damage by avoiding drops, rough handling and bruising during the different steps of pack house operations. Secondly the pack house operations should be carried out in shaded area. Shade can be created using locally available materials like, shade cloth, woven mats, plastic tarps or a canvas sheet hung from temporary poles. Shade alone can reduce air temperatures surrounding the produce by 8-17°C.
i) Dumping: The first step of handling is known as dumping. It should be done gently either using water or dry dumping. Wet dumping can be done by immersing the produce in water. It reduces mechanical injury, bruising, abrasions on the fruits, since water is more gentle on produce. The dry dumping is done by soft brushes fitted on the sloped ramp or moving conveyor belts. It will help in removing dust and dirt on the fruits.
ii) Pre-sorting: It is done to remove injured, decayed, mis-shapen fruits. It will save energy and money because culls will not be handled, cooled, packed or transported. Removing decaying fruits are especially important, because these will limit the spread of infection to other healthy fruits during handling.
iii) Washing and Cleaning: Washing with chlorine solution (100-150 ppm) can also be used to control innoculum build up during pack house operations. For best results, the pH of wash solution should be between 6.5-7.5
- Mangoes, bananas should be washed to remove latex.
- Kiwifruit should be dry cleaned or brushed after curing or storage.
iv) Sizing / Grading: Grading can be done manually or by automatic grading lines. Size grading can be done subjectively (visually) with the use of standard size gauges. Round produce units can be easily graded by using sizing rings.
Several types of mechanical sizes are available for small scale operations. One type is composed of a long slanted tray with a series of opening which coverage (largest at the top, smallest at the bottom). This type of sizes works best with round commodities.
The grading of fruits plays an important role in domestic and export marketing of fruits. Different fruits have different grades on the basis of their size and weight.
Grade designation and quality of fruits: Minimum requirements are :
Fruits should be
a) clean, round, free from any visible foreign matter
b) fresh in appearance, free of pests
c) free from damage caused by pests or diseases
d) free of any foreign smell and/or taste
The grades of different fruits and vegetables suggested by Directorate of Marketing and Inspection (DMI) are as under:
Kinnow
Size code Fruit Size No. of fruits in 10
(diameter) mm kg pack
A 60-64 84 B 65-69 72
C 70-72 60
D 72-74 54
E 75-79 51
F 80-85 45
Mangoes
Grade Fruit weight (g) Max. permissible difference between fruits
within packages (gm)
A 100-200 50
B 201-350 75
C 351-550 100
D
Grapes 551-800 125
Grade Large berries bunch weight (g) Small berries bunch weight (g)
Extra class 200 150
Class I 150 100
Class II
Guava 100 75
Size code Weight (gm) Diameter (mm)
A >350 >95
B 251-350 86-95
C 201-250 76-85
D 151-200 66-75
E 101-150 54-65
F
Litchi 61-100 43-53
Grade Fruit Diameter
(mm)
Extra class 33
Class I 28
Class II
Pomegranate 23
Grade Fruit weight (g)
Diameter (mm)
A 400 90
B 350 80
C 300 70
D 250 60
E 200 50
Cabbage
Size Code Weight in gms.
A 201-600
B 601-1200
C
Tomato
1201 and above
Size Code Diameter (in mm.)
Minimum Maxiumum
1 From 30 to 34
2 From 35 to 39
3 From 40 to 46
4 From 47 to 56
5 From 57 to 66
6 From 67 to 81
7 From 82 to 101
8
Onion
From 102 and above
Size code Diameter (in Difference between the diameter mm.) of the smallest and largest onion in the same package (in mm.)
A 10-20 5
B 21-40 15
C 41-70 20
D 71 and above 30
B) Precooling of Horticulture Produce
Pre-cooling of the produce soon after their harvest is one of the important components of the cool chain, which ultimately affect the shelf life of the produce. The main purpose of precooling is to immediately remove the field heat from the produce.
Method of pre-cooling :
- Room cooling
- Forced air cooling
- Hydrocooling
- Vacuum cooling
- Package icing
i) Room cooling : It is low cost and slow method of cooling. In this method, produce is simply loaded into a cool room and cool air is allowed to circulate among the cartons, sacks, bins or bulk load.
Advantages:
- Produce can be cooled and stored at the same