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 sasa@ufl.edu

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

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!

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

Delayed Harvest may result in softer fruit

Fruit detachment force: cultivar, harvest maturity for 2 harvests

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

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.

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

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

Field Trans-portation Typical handling steps and potential for mechanical damage Blueberry Handling Bush: Harvest Bucket Field Pre- sorting Field Trans-portation Lugs/ Pallet 1 2 3 4 5 Farm level Potential point of damage Loading / unloading

Receiving/packing/cooling facility Road Transp. Shipping 7 8 9 10 11 Loading / unloading Potential point of damage Overnight Cold Storage Sort/ Grade/ Pack/ Palletize Rapid Cooling/ Storage

Blueberry harvest Transfer to field lug

Mobile collection/pregrading station

Portable collection/pregrading station

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

Transfer to packing area

Impact Damage to Fresh Blueberries

Impacts affect aroma volatiles Freshly harvested blueberries dropped 6 times from 8 inches (20 cm) and stored @ 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)

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

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.

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

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

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).

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

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.

Storage Quality

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

Firmness During Storage Delays to Cooling: Results Firmness During Storage

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 (%)

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

Inserting temperature sensor Probed berries in center layer of pallet

Forced-air precooler Transport to packinghouse

Before packing Packed, ready for final cooling

Time/Temperature History

  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

  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

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

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

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

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

Questions??