Vegetable Crops – PLSC 451/551
Lesson 7, Harvest, Handling, Packing
Instructor:
Stephen L. Love
Aberdeen R & E Center
1693 S 2700 W
Aberdeen, ID 83210
Phone: 397-4181 Fax: 397-4311
Email: [email protected]
Vegetable Handling
Maximum quality exists at the moment
of harvest
Quality Maintenance
Limit mechanical injury
Limit losses to disease
Meet biochemical and culinary quality specifications
Vegetable Handling - Principles
Factors that determine post-harvest quality
Stage of crop maturity
Harvest and handling injury
Water loss
Temperature during harvest, transport and
storage
Rate of respiration, ripening, and breakdown
Infection with pathogenic organisms
Crop Maturity
Harvest Timing
Factors that modify harvest decisions:
Crop
Market availability
Commodity price
Intended use
Crop Maturity
Basis for harvest timing decisions
Harvest index based on:
Size
Color
Ability to withstand handling, storage, and
transport
Tendency for post-harvest ripening
Crop Maturity
Examples of maturity index characteristics:
Cantaloupe: fruit color and stem slip
Tomato: fruit color
Broccoli: head size and floral development
Lettuce: head and/or leaf size
Sweet corn: kernel color, kernel starchiness
Crop Maturity
Examples of maturity index characteristics:
Cantaloupe: fruit color and stem slip
Tomato: fruit color
Broccoli: head size and floral development
Lettuce: head and/or leaf size
Sweet corn: kernel color, kernel starchiness
Crop Maturity
Examples of maturity index characteristics:
Cantaloupe: fruit color and stem slip
Tomato: fruit color
Broccoli: head size and floral development
Lettuce: head and/or leaf size
Sweet corn: kernel color, kernel starchiness
Crop Maturity
Examples of maturity index characteristics:
Cantaloupe: fruit color and stem slip
Tomato: fruit color
Broccoli: head size and floral development
Lettuce: head and/or leaf size
Sweet corn: kernel color, kernel starchiness
Crop Maturity
Examples of maturity index characteristics:
Cantaloupe: fruit color and stem slip
Tomato: fruit color
Broccoli: head size and floral development
Lettuce: head and/or leaf size
Sweet corn: kernel color, kernel starchiness
Crop Maturity
Examples of maturity index characteristics:
Onion: drying and falling of tops
Potato: top death and skin-set
Carrot: length and diameter of root
Radish: size, time from planting
Cucumbers: size, color, firmness
Crop Maturity
Examples of maturity index characteristics:
Onion: drying and falling of tops
Potato: top death and skin-set
Carrot: length and diameter of root
Radish: size, time from planting
Cucumbers: size, color, firmness
Crop Maturity
Examples of maturity index characteristics:
Onion: drying and falling of tops
Potato: top death and skin-set
Carrot: length and diameter of root
Radish: size, time from planting
Cucumbers: size, color, firmness
Crop Maturity
Examples of maturity index characteristics:
Onion: drying and falling of tops
Potato: top death and skin-set
Carrot: length and diameter of root
Radish: size, time from planting
Cucumbers: size, color, firmness
Crop Maturity
Examples of maturity index characteristics:
Onion: drying and falling of tops
Potato: top death and skin-set
Carrot: length and diameter of root
Radish: size, time from planting
Cucumbers: size, color, firmness
Crop Maturity
Some crops can be harvested at multiple
stages of growth, but handling practices will
be modified at each stage.
Tomato - green pick, pink stage, vine ripened
Squash – immature, mature
Potato – new potatoes, mature
Harvest and Handling Injury
Most vegetable losses result from harvest and
handling damage
Blemishes resulting from bruising
Increased respiration
Moisture loss from damaged tissue
Entrance wounds for pathogens
Impact of injury on ripening and shelf-life of tomatoes
Handling Injury
Effect of drop height and picking stage:
Percent bruised fruit
0 in drop, green stage – 0%
12 in drop, green stage – 1.8%
0 in drop, breaker stage – 0%
12 in drop, breaker stage – 24.3%
Harvest Practices
Mechanical harvest:
Root crops, tuber crops, bulb crops, many
processing vegetables
Manual Harvest
Most vegetables including leafy greens, salad
crops, fruit vegetables, crucifers, and herbs
Harvest Practices
Mechanical harvest:
Root crops, tuber crops, bulb crops, many
processing vegetables
Manual Harvest
Most vegetables including leafy greens, salad
crops, fruit vegetables, crucifers, and herbs
Harvest Practices
Preventing mechanical harvest damage
Harvest only well-matured crops
Proper machine calibration and maintenance
Padding on all surfaces
Minimize drop heights
Operate all equipment at full capacity
Harvest Practices
Preventing manual harvest damage
Train labor to handle produce gently
Harvest at the proper stage of maturity
Field pack where feasible, minimize handling
Have labor trim fingernails or wear gloves
Use padding on all conveyor surfaces and
packing containers
Water Loss
Effects of water loss:
Quality reduction – shriveling and desiccation
Excessive trim losses
Loss of salable weight
Water Loss
Methods for reducing water loss:
Harvest and handle in cool conditions
Harvest well-watered crops
Rapidly cool produce to proper storage
temperatures
Employ humidification procedures
Water Loss
Optimum humidity level:
Asparagus
95-100%
Beet
98-100%
Sweet corn
95-98%
Garlic
60-70%
Lettuce
98-100%
Watermelon
90%
Pepper (dry)
60%
Pepper (bell)
90-95%
Temperature
Impact of improper temperatures
Above optimum
High rate of respiration and ripening
High rate of water loss
Rapid growth of decay organisms
Below optimum
Frost injury
Cold injury
Temperature
Vegetables that require cooling
Leafy greens and salad crops
Vegetable fruits with high respiration rates
Any crop with a short shelf-life
All crops when temperatures are very high
Temperature
Cooling techniques and equipment
Room cooling
Forced-air cooling
Hydro-cooling
Top-icing
Vacuum cooling
Evaporative cooling
Top-down cooling room
Forced-air cooling room
Portable cooling chamber
Hydro-cooler
Hand hydro-cooling
Icing
Vacuum cooler
Temperature
Optimum storage temps, cooling method, and
shelf life
Broccoli
32
HC,ICE
10-14 d
Cabbage
32
RM
5-6 m
Cucumber
50
HC
10-14 d
Okra
45
FA
7-10 d
Squash
50
RM
2-8 m
Sweet corn
32
HC,VAC 5-8 d
Ginger
60
RM
6m
Packing, Storing, Marketing
The shelf life and period of effective storage
of vegetables is determined by respiration
and ripening.
Respiration: the process by which cells produce
energy through oxidation of sugars and other
energy-rich compounds
Ripening: irreversible softening and sweetening
process by which vegetables become more edible
Packing, Storing, Marketing
Vegetable crops differ widely with respect to
rates of respiration and ripening
Root Crops: low rates of respiration and
small ripening changes
Packing, Storing, Marketing
Vegetable crops differ widely with respect to
rates of respiration and ripening
Leafy Crops: high rates of respiration and no
or minor ripening changes
Packing, Storing, Marketing
Vegetable crops differ widely with respect to
rates of respiration and ripening
Mature fruits: intermediate rate of
respiration and significant ripening changes.
Packing, Storing, Marketing
Vegetable crops differ widely with respect to
rates of respiration and ripening
Immature Fruit Crops: high rates of
respiration and incomplete ripening
processes
Rate of Respiration, Ripening
Sample of respiration rates
Very Low:
Low:
Moderate:
High:
Very High:
peanut
potato, onion, sweet potato
tomato, lettuce, pepper
green onions, snap beans
broccoli, peas, sweet corn
Rate of Respiration, Ripening
Importance of respiration rate
High respiration
= rapid changes (decline) in quality
= need for rapid handling and transport
= short storage capabilities
= short shelf life
Rate of Respiration, Ripening
Impact of temperature
Respiration can be controlled by lowering
temperature
For every 18 degree F above optimum, the rate of
deterioration doubles or triples (i.e. sweet corn at
50 (32) has shelf life of 2-4 days (4-8)
Ripening, Production of Ethylene
Vegetable that produce or are sensitive
Produce:
cantaloupe, tomato, pepper
many tree fruits often shipped with vegetables
Sensitive:
tomato, lettuce, cabbage, cauliflower, eggplant,
okra, pepper, squash, watermelon
Ethylene Injury
Symptoms on Vegetables
Carrots – bitterness
Cole Crops – turn yellow and limp
Cucumbers – turn yellow and develop soft spots
Asparagus – become fibrous and woody
Lettuce – develop rust-spots
Squash – turn yellow and develop soft spots
Rot and Breakdown
Rot in storage requires three things:
Susceptible host (vegetable)
All vegetable crop are prone to some disease
Pathogenic organism
Mostly fungal or bacterial
Proper conditions or environment
Temperature and humidity are critical
Rot and Breakdown
Conditions that increase incidence of rot
Entry wounds and tissue damage
High humidity
High temperature
Lack of adequate ventilation
Packing Vegetables
Importance of proper packaging
Provides conditions for quality maintenance
Improves shelf life
Identifies the produce
Simplifies shipping
Creates sales appeal
Packing Vegetables
Common steps in packaging produce
1. Washing
2. Presizing
3. Grading and Sizing
4. Trimming, waxing, cosmetic improvement
5. Packaging
6. Inspection
7. Palletizing
Packing Vegetables
Common steps in packaging produce
1. Washing
2. Presizing
3. Grading and Sizing
4. Trimming, waxing, cosmetic improvement
5. Packaging
6. Inspection
7. Palletizing
Packing Vegetables
Common steps in packaging produce
1. Washing
2. Presizing
3. Grading and Sizing
4. Trimming, waxing, cosmetic improvement
5. Packaging
6. Inspection
7. Palletizing
Packing Vegetables
Common steps in packaging produce
1. Washing
2. Presizing
3. Grading and Sizing
4. Trimming, waxing, cosmetic improvement
5. Packaging
6. Inspection
7. Palletizing
Packing Vegetables
Common steps in packaging produce
1. Washing
2. Presizing
3. Grading and Sizing
4. Trimming, waxing, cosmetic improvement
5. Packaging
6. Inspection
7. Palletizing
Packing Vegetables
Common steps in packaging produce
1. Washing
2. Presizing
3. Grading and Sizing
4. Trimming, waxing, cosmetic improvement
5. Packaging
6. Inspection
7. Palletizing
Packing Vegetables
Common steps in packaging produce
1. Washing
2. Presizing
3. Grading and Sizing
4. Trimming, waxing, cosmetic improvement
5. Packaging
6. Inspection
7. Palletizing
Packing Vegetables
Similar process, smaller scale, less automation
Grade Standards for Vegetables
Purpose of grade standards
Ensure quality for the seller and buyer
Provide a common language for quality
Provide legal protection for all parties
Provide third party confirmation
Grade Standards for Vegetables
Origin of published grade standards
USDA/AMS
State departments of agriculture
Local marketing order organizations
Local grower groups
Individual sellers and buyers
Grade Standards for Vegetables
USDA Standards
158 published standards
85 vegetable crops
Include specifications for size, shape, defects,
damage
Web site: http://www.ams.usda.gov/gac/index.htm
Grade Standards for Vegetables
Enforcement of grade standards
Inspections conducted by Federal/State
inspectors
Packing-site inspections
Shipping point inspections
Receiving point inspections
Grade Standards for Vegetables
Application of standards
Commercial U.S. Production
USDA-AMS grading standards applied
Organic/Market Production
Variable: grade and/or organic standards
often applied in developed countries
Worldwide subsistence production
No application of standards