I HAVE TRIED TO BRIEF ABOUT EFFECT OF HOT WATER TREATMENT ON POST HARVEST INSECT AND DISEASE MANAGEMENT.

1. 1

2. 2

3. 3

4. UNIVERSITY OF HORTICULTURAL SCIENCES
BAGALKOT
Name of the Student : Ayeeshya Kolhar
I.D. No. : UHS17PGD223
Degree Programme : Ph.D. (Hort.)
Department : Post Harvest Technology
Role of hot water treatment in controlling
postharvest insect and diseases in fruits
4

5. Introduction to HWT
Method of HWT
Mode of action
Applications of HWT
Case study
Conclusion
5

6. UniversityofHorticulturalSciences,Bagalkot
Introduction
• Hot water treatment- fruits are immersed in hot water
before storage or marketing
• Pre-storage hot treatments followed in many fruits
• Insect control
• Postharvest diseases
• Postharvest decay
• Hot water treatments were first reported in 1922 to control
decay on citrus fruit (Fawcett, 1922)
6

7. Mode of entry for insect and pathogens
• Natural openings
• Stress induced openings
• Direct penetration (some fungi)
• Wounds (insect)
• Mechanical damage
7

8. Table 1: Major post harvest diseases and pests of fruits
Crop Disease Pathogens
Apple & Pear Blue mould Pencillium expansum
Banana Crown rot Colletotrichum musae, Fusarium roseum
Citrus fruit Green mould Pencillium digitatum
Mango & Papaya Anthracnose Colletotrichum gloeosporioides
Host Insect Scientific names
Mango and Ber Fruit fly Bactocera dorsalis
Mango Stone weevil Sternochitus mangiferae
Apple Codling moth Cydia pomonella
Fallik, 2004
8

9. 1. Hot Water Immersion (HWI)
2. Hot Water Rinsing & Brushing (HWRB)
Methods of HWT
9

10. 1. Hot water immersion (HWI)
• Main components of a hot water immersion unit are
 Treatment tank
 Heat exchanger unit
 Water circulation system
 Temperature controller
Hot Water Tank
Produce
10

11. Hot water immersion unit
11

12. Effects of hot water treatment on anthracnose disease
in papaya fruit and its possible mechanism
Xueping et al., 2013
Postharvest Biology and Technology, 89: 56-58
12

13. Objective -
• To elucidate the effect of HWT on physiological defence reactions
Treatments-
• Control - Dipped in water at normal temperature ( 25˚C ) for 4 min
• Treatment with 54˚C for 4 min
Materials & Methods:
• Papaya fruit cv. ‘Sunrise’
• Dipped in 0.3% hypochloride solution for 10 min.
13

14. Figure-1: Colour index of hot water treated and untreated fruits
Xueping et al., 2013
14

15. Figure-2: Water soluble pectin content (%) of hot water
treated and untreated fruits
Xueping et al., 2013 15

16. Figure-3 : The effects of HWT on the (A) The carrier rate of Colletotrichum
gloeosporioides in fruit peel. (B) anthracnose. (C and D) stem end
rot. Xueping et al., 2013
16

17. Figure-4: Structural changes of epicuticular wax induced by
hot water treatment
Xueping et al., 2013 17

18. Hot water as an effective post harvest disinfestation
for the oriental fruit fly, Bactocera dorsalis on mango
Verghese et al., 2011, IIHR Bengaluru
Pest Management in Horticultural Ecosystems,
Vol.17,No.2 pp63-68(2011)
18

19. Objective-
• To standardize a temperature - time regime for Alphonso and Totapuri variety
against fruit fly infestation
• 6 treatments – 30 fruits (each treatment)
• Hot water treatment - 46˚C for 60 mins, 48˚C for 60,75 and 90 minutes
Materials & Methods:
• Alphonso and Totapuri mangoes
• Oriental fruit fly
Treatments-
19

20. 20
Table-2: Percentage B. dorsalis infestation at different
temperature-time regimes
Temperature
˚C
Time
min
Alphonso Totapuri
2004 2005 2004 2005
46 60 0.00 0.00 0.00 0.00
48 60 0.00 0.00 0.00 0.00
48 75 0.00 0.00 0.00 0.00
48 90 0.00 0.00 0.00 0.00
Pre- harvest IPM 1.11 2.22 4.30 1.11
Control 33.33
(287)
13.33
(122)
40.00
(316)
3.33
(26)
Pre-harvest IPM- without exposing to laboratory adults
Control-not exposed to hot water treatment
Figures in the parenthesis are number of larvae of larvae found in 30 fruits
Verghese et al., 2011

21. 21
Table 3 : Quality acceptability quotient (QAQ)
Alphonso Taste (%) Colour (%)
Control Treated Control Treated
Excellent 33.33 46.67 33.33 66.67
Very good 53.33 33.33 33.33 26.67
Good 13.33 20.00 33.33 6.67
Bad 0.00 0.00 0.00 0.00
Very bad 0.00 0.00 0.00 0.00
Totapuri Taste (%) Colour (%)
Control Treated Control Treated
Excellent 13.33 20.00 60.00 80.00
Very good 26.67 40.00 40.00 20.00
Good 40.00 33.33 0.00 0.00
Bad 20.00 6.67 0.00 0.00
Very bad 0.00 0.00 0.00 0.00
Verghese et al., 2011

22. Effects of hot water treatment on the storage stability of
Satsuma mandarin as a postharvest decay control
Hong et al., 2007
Postharvest Biology and Technology
22

23. Objective-
• To study the effect of hot water dips on the post harvest quality and spoilage of
Satsuma mandarin.
Treatments-
• Control - Fruits dipped in cold tap water (7–10 °C ) for 2 min
• Hot water dipping at 52 °C for 2 min, 55 °C for 1 min, and 60 °C for 20 s
• Packaged in perforated plastic film bags (35 cm×45 cm)
• Stored - 5°C for 3weeks and subsequently for 1 week at 18°C
Materials & Methods:
• Satsuma mandarin (Citrus unshiu Marc., cv. Gungchun)
• Thermometers
23

24. Figure-5: Changes in decay ratio of Satsuma mandarin fruit treated with
hot water dips under various conditions during storage at 5 ˚C
for 21 days and at 18 ˚C for a subsequent 7 days.
Hong et al., (2007)
24

25. Figure-6: Changes in decay ratio of Satsuma mandarin fruit treated with hot
water dips under various conditions during storage at 5˚C for 21
days and at 18 ˚C for a subsequent 7 days.
Hong et al., (2007)25

26. Hong et al., 2007
Table 4: Changes in sensory scores of Satsuma mandarin fruit
treated with hot water dips under various conditions
during storage
26

27. 2. Hot Water Rinsing & Brushing (HWRB)
(1) Conveyor belt
(2) Tap water rinsing and brushing unit
(3) Hot water rinsing and brushing unit. (Water is recycled)
(4) Hot water container
(5) Water pump to pressurize and recycle the hot water
(6) Forced-air dryer.
• To clean and disinfect
fresh harvested
produce.
• First introduced
commercially in 1996
27Fallik et al., 1996

28. Hot water brushing: an alternative method to SO2
fumigation for colour retention of litchi fruits
Postharvest Biology and Technology
Lichter et al., 2000
28

29. Objective-
• To evaluated the effect of HWB in combination with acid dipping on the
quality of litchi fruit.
Treatments-
• Control - Fruits dipped in cold tap water (7–10 °C ) for 2 min
• SO2 treatment + Acid solution - 4% food-grade HCl and 0.2% prochloraz
• HWB (55°C for 20 sec) + Acid solution - 4% food-grade HCl and 0.2%
prochloraz
• Storage for 3 weeks (1.5°C, RH-95%)
Materials & Methods:
• Lychee chinensis . cv. Mauritius
• Packed in 2 kg open cardboard boxes
29

30. Figure-8: The appearance of litchi fruits after different
postharvest treatments
Lichter et al., 2000 30

31. Figure-9: The appearance of litchi fruits after different
postharvest treatments. Storage time was 3 weeks at
1.5°C and 5 days at 20°C.
Lichter et al., 2000 31

32. 32
• Clear redistribution of the epicuticular wax layer
(Schirra and D’Hallewin, 1997)
• Heat treatments inhibit biochemical pathways involved in many
fruit and vegetables (Paull and Chen, 2000)
• Increases in the accumulation of glucanase and chitinase proteins
(Pavoncello et al., 2001)
• Build up resistance responses to host
(Nafussi et al., 2001)
• Induce resistance against chilling injury or pathogen infection
• Reduced enzymatic activity
• Removes soil and dust and also fungal spores from the fruit surface
Mode of action

33. Combination treatments
1. Hot water treatment and fungicides
 Hot water treatment at 52°C for 10 min combined with the
fungicide bavistin at 0.1 mL/L
(Fallik, 2011)
Anthracnose Stem-end rot 33

34. 2. Hot water treatment and Biocontrol
• At present there are two commercial products available for
postharvest use
1. Biosave - Pseudomonas syringae
2. Shemer - Metschnikowia fructicola
• Hot water treatment 50°c in combination with bio control agent
(Debaryomyces hansenii) reduced the postharvest decay and
extend shelf life of peaches.
(Sharma et al., 2007)
34

35. 3. Hot water treatment and Ethanol
• Potent antimicrobial activity
• Immersion in 10% Ethanol at 50°C for 60 seconds
significantly reduced the decay of grape berries during
storage for 30 days at 1°C
(Karabulut et al., 2004)
35

36. 4. Hot water and Modified atmosphere packaging
• Nectarines and peaches HWT at 46°C for 25 min, sealed in
thin polyethylene bags, and stored at 0°C for 1 and 2 weeks
• Hot water combined with MAP maintained good fruit quality
during storage
(Malakou and Nanos, 2005)
36

37. 37

38. Introduction
• To export of fresh apples to mainly Japan and South
Korea require quarantine treatments against codling
moth, Cydia pomonella L
• Codling moth can damage 80 to 95 % making it
“wormy” and unfit to eat
• Earlier Methyl bromide is used commercially but
postharvest quarantine treatment of Methyl bromide
currently banned
38

39. Solutions for this enemy are…..
Pre-harvest fruit bagging
HWT
Application of particle films
39

40. • Objectives
• To investigate the effectiveness of RF thermal treatments against codling
moth in apples, and to evaluate the postharvest quality of treated apple
• Materials
• Red Delicious’ apples
• Codling moth larvae
• 7 apples and 35 larvae per replicate were enclosed in a single ventilated
plastic container
• Pack in ventilated container
• Store at 22 ˚C , 60–70% RH, and 16:8 h light : dark
• Control 2 fruits (unheated)
1 kept at air
1 kept at water
40

41. Sub-surface
Core
Wang et al. , 2006
Figure-11: RF heating system description and treatment procedure
41

42. Figure-12: Contour plot of temperature distribution obtained by thermal
imaging over horizontal and vertical apple cross sections
Water preheating 45°
c , 30 min
RF heating from
45° -48° c , 1.25
min
v
48
48
v
48
v
v
36
44
v48
48
v
v
36v
42v
Non uniform heating
Uniform heating48
Wang et al., 2006

43. Water holding, 48° c
Hydrocooling , 30
min
48
4848
48
48
48
48
48
48
v
v
v
v
v
v
v
4
10
12
18
16
v
v
Uniform distribution
of heat in whole fruit
Hence RF Treatement
helps in uniform heating
of fruit
Wang et al., 2006

44. Temperature +
holding time
Total no. of alive
instars
Total no. of dead
instars
Mortality (%)
Control at room air 99 6 5.7 ± 2.9
Control at room
water for 80 min
96 9 8.6 ± 2.9
45°c + 30min - RF 85 20 19.1 ± 8.7
48°c + 5min + RF 3 102 97.1 ± 2.9
48°c +10min + RF 2 103 98.1 ± 1.7
48°c + 15min + RF
0 105 100 ± 0
48°c + 20min + RF 0 105 100 ± 0
Table 4: Total number of live and dead fifth-instar codling moths
recovered from ‘Red Delicious’ apples with the mortality
Wang et al., 2006

45. Source Weight loss (%) Firmness (N)
Waxed 0.82a 74.28
Unwaxed 1.20b 73.91
Treatment
Control 1.93d 65.71a
48 ◦C+ 10 min 0.52a 76.00b
48 ◦C+ 15 min 0.75b 77.81b
48 ◦C+ 20 min 0.84c 76.85b
Table-5: Quality attributes of ‘Red Delicious’ apples subjected to RF heat
treatments
Wang et al, 2006

46. UniversityofHorticulturalSciences,Bagalkot
Advantages
 Controlling insect pests
 Reduces post harvest rots
 Better shelf life
 Reduces chilling injury
 Making possible the use of postharvest fungicides at lower
concentrations
Fallik, 2004 46

47. Table 6: Applications of HWT in different fruit crops
Crop Treatment Optimal temp ˚C
(time)
Aim Reference
Mango HWT 43–49 (65–90 min) Quarantine Jacobi et al.,2001
Apple (cv.
Golden Delios)
HWRB 55 (15 s) Decay control,
ripening inhibition
Fallik et al., 2001
Avocado (cv.
‘Hass’)
HWT 38 (60 min) Chilling prevention Woolf, 1997
Lemon HWT 52–53 (2 min) Decay control, decay
resistance
Nafussi et al., 2001
Litchi HWRB 55 (20 s) Decay control Lichter et al., 2000
Plum (cv. Friar) HWT 45–50
(35–30 min)
Decay control,
chilling resistance
Abu-kpawoh et al.,
2002
Orange (cv.
Shamouti)
HWRB 56 (20 s) Decay control, better
quality
Porat et al.,2000
47

48. Limitations of HWT
It may injure the produce
It does not provide protection against heat resistant pathogens
There may be increased water loss from the produce
Discoloration of produce may occur
Spoilage of fruits
48

49. UniversityofHorticulturalSciences,Bagalkot
49
Fresh fruits need to be free of disease agents,
insects and synthetic chemicals, and cleaned
of any dirt or dust before being packed for
export
Postharvest use of fungicides is potentially
harmful to humans
Conclusion

50. 50
THANK YOU…