1. POSTHARVEST HANDLING OF
CUCUMBERS

2. WHAT IS CUCUMBER? Cucumis sativus L. of Cucurbitaceae family.
Plant of tropical origin (India?)
Relative of melons, pumpkins, squashes, watermelons
In contrast to most of them – harvested immature (young)
Greenhouse cucumbers: parthenocarpic, develop without pollination. Smooth tender skin, eaten without peeling
Types of greenhouse cucumbers: European (or Dutch, English) type – long and Beit-Alpha type (Israeli origin) – short. Beit Alpha type gives 2-3 times higher yield than the Dutch type, and better fruit quality (but the Dutch tends to be more resistant to powdery mildew).
Dutch type
Beit-Alpha type

3. Senescence-related changes in cucumbers
Postharvest biology of cucumber = Postharvest problems of cucumber
Immature fruit: tends to continue the development → yellowing, change of texture and taste
Senescence-related changes in cucumbers
SENSITIVE TO ETHYLENE! NOT TO BE KEPT WITH ETHYLENE-PRODUCING COMMODITIES: TOMATOES, AVOCADO, BANANA, APPLE, PEAR, FIG, MELON, etc.

4. AIR HUMIDITY IS IMPORTANT: 90-95%
Tender skin: tends to
easily lose water →
SENSITIVE TO DESICCATION
Shriveling
AIR HUMIDITY IS IMPORTANT: 90-95%
WHY NOT HIGHER? Water condensation favors disease development.
SENSITIVE TO POSTHARVEST DISEASES

5. Major postharvest pathogens of cucumber (in Israel): fungi Botrytis, Sclerotinia, bacterium Pseudomonas lachrymans
Sclerotinia
Botrytis cinerea
P. lachrymans
The Botrytis attacks damaged (e.g., by low temperature) or senescent tissues (=“dieing”). Stimulated by ethylene.
The Botrytis decay often starts the blossom end (from the flower residue). If possible, the flower residue should be removed. The Botrytis at the stem end usually results from inaccurate picking (smashed peduncle).
Combination of Botrytis and P. lachrymans.

6. Develops chilling injury at temperatures below 9°C
Tropical/subtropical origin → VERY SENSITIVE TO LOW STORAGE TEMPERATURE
Develops chilling injury
at temperatures below 9°C
Pitting: a chilling injury symptom
OPTIMAL STORAGE TEMPERATURE 10-11°C
The chilling injury often transforms into fungal rots
Another postharvest disorder: development of warts during storage of initially smooth cucumbers

7. Postharvest technology : Trying to solve the problems
Harvest criteria:
size (for Beit Alpha type): diameter mm, length mm); smooth, glossy dark-green skin.
Sanitation at harvest:
clean tools; avoiding contact of fruit with soil / substrate.
Reducing mechanical damage: accurate hand-picking. Avoid dropping fruit, minimum transfers. Selective picking.

8. Postharvest procedures
Local market (currently – most of the cucumbers)
Transfer into 12-kg plastic boxes lined with perforated polyethylene bag (to reduce moisture loss)
Transportation to “logistic centers” of marketing companies or wholesale market (up to 2-3 hours)
Harvesting
Marketing on open shelves (up to 2 days) at ≥ 20C and 50-70% RH
Storage at “logistic centers” up to 3 days at 15-17C and 85-90% RH
MAJOR STAGE OF DETERIORATION

9. Retail packaging: protection for the produce on the shelf
PVC-wrapped tray
Long “European” (= “Dutch”, “English”) greenhouse cucumbers: individually shrink-wrapped (no photo shown)
US: waxing (usually peeled before eating)
Bags (Japan)

10. Fresh-cut cucumbers (supermarket, China)

11. Transfer to packing facility Sorting by size and shape
Local market (advanced scheme, currently in progress)
Hot water wash
(55-58C, 15-20”,
no brushes!), drying
Transfer to packing facility
Harvesting
Transportation to “logistic centers” of marketing companies or wholesale market (up to 2-3 hours)
Packaging into polyethylene-lined plastic boxes
Sorting by size and shape
Retail packaging
Storage at “logistic centers” up to 3 days at 15-17C and 85-90% RH
Marketing on open shelves at ≥ 20C and 50-70% RH

12. SORTING AND PACKAGING Automated packing-house for cucumbers, Japan
Cooperative of ~10 growers
Optical sorting facility

13. Export (mostly cucumbers from “organic” growing)
Transfer to packing facility
Sorting by diameter
Harvesting
Packaging in 4-kg boxes (2 layers of fruit) with Xtend bags (liners)
Gentle wiping with soft and clean tissue, removal of flower residue
Quality control and transportation to export outlet
Shipment to Europe by sea: up to 12 days at 10-11C
Marketing in Europe
MAJOR POTENTIAL FOR DETERIORATION

14. Xtend liners have higher water vapor permeability than polyethylene.
“Xtend” effects: combination of modified atmosphere (MA) and modified humidity (MH) packaging
Xtend liners allow accumulation of increased CO2 concentration due to the produce respiration (modified atmosphere). CO2 inhibits ethylene.
Xtend liners have higher water vapor permeability than polyethylene.
They allow optimal RH level of 92-97%, reduce weight loss and prevent the accumulation of condensed water.

15. Effects of Xtend packaging on cucumbers
12 days at 10C +3 days at 20C
3 days at 10C+ 3 days at 20C
Inhibition of yellowing
Inhibition of decay
Comparison with perforated polyethylene liner (as for local market) and non-packaged fruit

16. Effects of Xtend packaging on chilling injury of cucumbers
Xtend packaging prevents external signs of chilling injury, but not the internal signs
Recommended to ship cucumbers in Xtend at optimal temperature of 10C

17. Potential problems with applying the Xtend packaging with cucumbers
1. Potential to CO2 damage (>10% CO2)
NOT TO OVERLOAD THE PACKAGES!
OBSERVE THE TEMPERATURE RECOMMENDATIONS!
OPEN THE PACKAGES AFTER TRANSFER TO SHELF-LIFE
(NON-COOLED) CONDITIONS!
CO2>12%
CO2<9%
CO2 damage to cucumbers
6 kg cucumbers in the liner for 4-kg load
2. High cost

18. THANK YOU!