1. Maintaining Blueberry Quality During Harvest and Handling Operations
Southeast Regional Fruit & Vegetable Conference
January 9, 2015
Maintaining Blueberry Quality During Harvest and Handling Operations
Steve Sargent
Extension postharvest horticulturist
Horticultural Sciences Department
University of Florida-IFAS

2. As your operation grows, so does your need for logistics
DEALING WITH SUCCESS!!
As your operation grows, so does your need for logistics
How do increasing yields affect:
Crew size needed for harvest
Fruit wait time in the field
Ability to minimize contamination
Transport volume/time to packinghouse
Time to cool to final pulp temperature

3. These studies were in part funded by a grant from the USDA/FDACS Specialty Crops Research Program
Collaborators:
Drs. Jeff Williamson, Jeff Brecht, Jim Olmstead, Jerry Bartz, Keith Schneider, Zhengfei Guan
Adrian Berry, Merce Santana
Florida Blueberry Growers Assn.
Florida Fruit & Vegetable Assn.
The generosity of our Florida blueberry growers and shippers!

4. To maintain high fruit quality…
KEYS FOR SUCCESS!!
To maintain high fruit quality…
Today we will focus on studies for:
Harvest at proper maturity
Minimizing mechanical damage
Managing fruit temperature

5. Delayed Harvest may result in softer fruit

6. Fruit detachment force: cultivar, harvest maturity for 2 harvests

7. How Does Harvest Time Affect Quality??
Cvs. Emerald, Jewel, Primadona were harvested early, mid and late season
For each harvest, fruit sorted and packed into 4.4 oz clamshells
Cooled and stored at 37 oF
Quality determined during 14 days storage

8. Weight loss after 0, 7, and 14 days at 37°F for harvests 1, 2, and 3.
There were some differences in blueberry quality due to harvest time and variety during the storage tests. After 14 days of storage, ‘Primadonna’ and ‘Emerald’ generally maintained good appearance, while ‘Meadowlark’, ‘Farthing’ and ‘Sweetcrisp’ were rated lower for two of three harvests. Weight loss did not always correlate with shriveling; ‘Jewel’ and ‘Meadowlark’ tended to have more shrivel symptoms than the other varieties, but only ‘Meadowlark’ had higher weight loss. ‘Jewel’ had 30% to 40% soft fruit for Harvests 2 and 3. ‘Primadonna’ had the highest sugar-acid ratio for the single harvest tested, as did ‘Meadowlark’ and ‘Farthing’. High soluble solids content in ‘Sweetcrisp’ was offset by high acid levels, lowering the sugar-acid ratio. Vitamin C concentrations were similar to those reported in the scientific literature.

9. Brix/acid ratio after 0, 7, and 14 days at 37°F
for harvests 1, 2, and 3.
2010 Season

10. Causes of Mechanical Damage
Fruit receive many impacts during harvest and handling

11. Field Trans-portation
Typical handling steps and potential for mechanical damage
Blueberry Handling
Bush:
Harvest
Bucket
Field Pre-
sorting
Field Trans-portation
Lugs/
Pallet
Farm level
Potential point of damage
Loading / unloading

12. Receiving/packing/cooling facility
Road
Transp.
Shipping
Loading / unloading
Potential point of damage
Overnight
Cold Storage
Sort/
Grade/
Pack/
Palletize
Rapid Cooling/
Storage

13. Blueberry harvest
Transfer to field lug

14. Mobile collection/pregrading station

15. Portable collection/pregrading station

16. Example of a well-designed field lug:
Cross-braces reduce vibration
Short height – better use of space
Good ventilation when stacked

17. Transfer to packing area

18. Impact Damage to Fresh Blueberries

19. Impacts affect aroma volatiles
Freshly harvested blueberries dropped 6 times from 8 inches (20 cm) and 36oF (2oC)
Aroma volatiles measured during storage (after 2, 10, 17, 24 days )
Discriminant function analysis performed after separation of blueberry volatiles (Demir et al. 2011)

20. Discriminant Function Analysis showed impacts caused differences in aroma volatiles during storage

21. Demand for fresh-market blueberries continues to rise (Perez & Plattner, 2012) while harvest labor is becoming more scarce (Fonsah et al., 2008).
Fruit are typically hand-harvested every 3 to 4 d during the picking season.
However, in order for the fruit to be suitable for mechanical harvest, the harvest interval would need to be extended to every 7 to 10 d.
This delay might accelerate fruit abscission and/or senescence.

26. Seasonal Packout: Hand v. Mech.
Meadowlark
Harvest Method
Marketable
Immature
Soft
Hand
92.1
6.2
1.7
Machine
84.1
11.9
4.0
Significance
0.0058
0.0133
0.0005
Farthing
Harvest Method
Marketable
Immature
Soft
Hand
94.3
4.5
1.2
Machine
80.5
17.3
2.2
Significance
0.0039
0.0051
0.0356
Sweetcrisp
Harvest Method
Marketable
Immature
Soft
Hand
95.3
3.7
1.0
Machine
77.4
20.6
1.9
Significance
0.0030
0.0006
0.0682

27. Visual Quality: Hand v. Mech. Harvest
Hand Harvested and Stored
Mech. Harvested and Stored
7 days
14 days
Cultiv.
App
Rat
Soft %
Shr %
Shr %
Harvest 1
M-lark
4.0
15.0
30.0
2.0
10.0
90.0
25.0
37.5
32.5
Farth.
17.5
3.0
27.5
5.0
75.0
50.0
Swtcrs
2.9
42.5
70.0

28. Flavor: Hand v. Mech. Harvest
Initial
Hand (14 d)
Mech. (14 d)
Cult.
SSC
TTA (%)
SSC/TTA
TTA %
M-lark
7.7
0.5
16.6
a B
8.2
0.42
19.7
b A
0.3
24.5
a AB
Far
10.8
0.7
16.3
a C
11.3
0.44
25.7
a A
10.7
20.9
Swcr
13.5
1.0
13.4
b B
13.7
0.82
16.9
c A
13.6
yMeans (n=4) followed by the same lower case letter in a column or capital letter in the same row are not significantly different according to Duncan’s Multiple Range Test (P<0.05).

29. Causes of Mechanical Damage
Fruit several impacts during mechanical harvest
Most severe occurs as the detached fruit falls to the catch plates on the harvester
This impact is believed to be the major cause of fruit softening during storage

30. Delays to harvest on quality
Objective: Evaluate mechanical and sensory quality of blueberries picked upon reaching blue color stage and after an additional 7 days on the plant.

31. Storage Quality

32. Weight loss during storage
Delays to Cooling: Results
Weight loss during storage

33. Firmness During Storage
Delays to Cooling: Results
Firmness During Storage

34. Delays to Cooling: Results
(hr)
Week 1
Week 2
Week 3
Week 4
50.0
42.5 2
47.5
22.5 4
40.0 6
35.0
60.0 8
27.5
70.0
Incidence of unmarketable fruit (%)

35. How long can cooling be delayed without affecting blueberry quality?
Spring 2015: we compared fruit quality that had been picked, packed and cooled
the day of harvest
the following day (26 hours)
Fruit quality was evaluated after 7 and 14 days of storage

36. Inserting temperature
sensor
Probed berries in
center layer of pallet

37. Forced-air precooler
Transport to
packinghouse

38. Before packing
Packed, ready for final cooling

39. Time/Temperature History

40. Storage
Time
Weight Loss (%)
Appearance
Shrivel
Decay
mean
same day na
5.00
0.00 7
0.71
0.05
7.25
1.50
0.25
0.50 14
0.76
0.08
4.25
13.25
1.89 21
1.85
0.13
2.75
19.25
1.71
0.58
next day
0.48
4.50
9.00
1.83
0.02
14.25
1.91
0.23
3.00
0.82
18.50
2.08
1.00

41. Storage
Time
Firmness (gf/mm)
oBrix
Citric Acid (%)
mean
same day
1.98
0.09
16.30
1.01
0.89
0.12
3.02
0.04 7
1.93
13.03
0.60
0.56
3.15
0.03 14
1.78
0.08
12.78
0.43
0.61
0.06
3.11 21
1.64
12.00
0.71
0.51
0.05
3.16
next day
1.91
11.98
0.59
1.96
0.07
12.23
0.36
0.55
3.14
1.74
11.68
0.64
0.47
0.10
3.20
1.87
0.13
11.90
1.57
0.17

42. Effect of drop on blueberry respiration rate Each fruit dropped
once from 20 inches

44. Conclusions (1) Weight loss: Fruit firmness: Fruit flavor:
Cultivar-dependent
Cooling delays over 6 hours = ↑ loss
↑ during storage
Fruit firmness:
↑ softening, abscission with delays to harvest
Fruit flavor:
Regular harvest time - minor effect
Delayed harvest time - sweeter

45. Conclusions (2) Mechanical Harvest (vs. Hand Harvest):
Cultivar differences
↑ soft fruit at harvest and during storage
Shrivel symptoms didn’t correlate with soft fruit
↓ flavor
Temperature Effects
Based on two tests, precooling to 50F reduced bruising from impact

46. Conclusions (3) Temperature Effects – 50F is critical pulp temp.
Precooling to 50F soon after harvest:
Minimized effect on storage quality when final cooling was applied 26 hours after harvest
Reduced bruising from impact

47. Questions??