Vegetable Crops – PLSC 451/551 Lesson 7, Harvest, Handling, Packing Instructor: Stephen L. Love Aberdeen R & E Center 1693 S 2700 W Aberdeen, ID Phone: Fax:

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: Asparagus95-100% Beet98-100% Sweet corn95-98% Garlic60-70% Lettuce98-100% Watermelon90% 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 Broccoli32HC,ICE10-14 d Cabbage32RM5-6 m Cucumber50HC10-14 d Okra45FA7-10 d Squash50RM2-8 m Sweet corn32HC,VAC5-8 d Ginger60RM6 m

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:peanut Low:potato, onion, sweet potato Moderate:tomato, lettuce, pepper High:green onions, snap beans Very High: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:

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