Section 15

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Fruit and Vegetable Harvest and Postharvest Operations

The following mind maps provide an outline that should be used in conjunction with the provided readings. A excellent additional reference is: “Postharvest Technology of Horticultural Crops” 2nd Edition Edited by A.A.Kader, published by University of California, Publication 3311. The subjects covered by the mindmaps include:

• harvesting • Transport to Packhouse • Packhouse operations

o Sorting Colour Size

o Packing • Quality Assurance

o HACCP • Packaging (Additional note)

EXERCISE: Using the Mindmaps as the basis, develop a more detailed summary of the readings provided. 1.0 REFERENCES

Wong, L.S. & Bagshaw, J., 2001. Assessment of the postharvest handling system for broccoli grown in the Lockyer Valley, Queensland, Australia. In Postharvest Handling of Fresh Vegetables, Proceedings of a workshop held in Beijing, 2001. Pub by Australian Centre for International: Agricultural Research, Cnberra, 2001, pp26-32 Prussia, S.E. & Shewfelt, R.L. 1993. Systems Approach to Postharvest Handling. Chapter in Postharvest Handling – A systems approach. Ed. by Shewfelt & Prussia, Pub. by Academic Press, San Diego. pp43-71. Chakraverty, A. & Singh, R.P., 2001. Postharvest Technology, Cereals, Pulses, Fruit and Vegetables. Published by Science Publishers, Inc. Enfield, USA.

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Wills, R., McGlasson, B., Graham, D. & Joyce, D., 1998. Postharvest. An Introduction to the physiology and handling of fruits, vegetables and ornamentals. 4th Ed., Published by UNSW. Handbook of Postharvest Technology. Cereals, Fruits, Vegetables, Tea and Spices. Edited by Chakraverty, A., Mujumdar, A.S., Raghavan, G.S.V. & Ramaswamy, H.S. Published by Marsel Dekker, New York, 2003. Kadder, A.A. (Ed), 1992. Postharvest Technology of Horticultural Crops, 2nd Edition. Publ by University of California, Pub No. 3311.

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FRUIT CROP HARVESTING AND

HANDLING

Fundamental Principles

Engineering

Traceability

Principles

Harvesting

Post-Harvest

System Performance Specification

Quality Assurance • Quality Attributes • Physical Parameters • Physical properties • Food safety • HACCP

Product Quality Safety

DEFINE Performance

Specification and Engineering

Quality Assurance

Value Chain

Food Safety

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SUPPLY CHAIN MANAGEMENT

7 Principles

Strategic Alliance

Relationship Management

FOCUS

DEVELOP CUSTOMER-DRIVEN PERFORMANCE MEASURES

BEGIN WITH CUSTOMER

MANAGE LOGISTICS ASSETS

ORGANISE CUSTOMER MANAGEMENT

INTEGRATE SALES AND OPRATIONS PLANNING

LEVERAGE MANUFACTURING AND SOURCING

• S.A.P. • J.I.T. • T.Q.M.

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ventilated

PRODUCE HANDLING

HARVEST

FIELD HEAT REMOVAL

TRANSPORTATION FROM FIELD

LIVING RESPIRING

TISSUE

STORAGE

USDA Handbook 66

Details

Incompatible Table 6

Chiller

Table 5

Payment

hourly

quality incentivest

Highly perishable cooler

early morning

night Harvest

Bruises/cuts

Quality selection

disease

insect bird

over maturity

Produce injury

improper picking

dropping

Dumping from picking container to transport centre

Trasnport containers

Overfilling Ride

crushing

base and top of container

bruisng rubbing

smooth

reducing tyre pressure

attention to tracks

Cooling

Methods

Sunlight/Heat

slows decay organisms

slows respiration

misting water okay

refrigeration water damage shade fruit vegetables

light coloured taurpaulin 10 cm gap between

tarpaulin and fruit allows airflow

Less field contamination

Removal of damaged or

spoiled produce

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HARVEST

AIM REDUCE

QUALITY SELECTION

HARVEST DATE

HIGHLY PERISHABLE

QUALITY

HAND HARVESTING

MACHINE AIDED

MACHINE HARVEST

Bruises (Table 6.1)

Cuts/injury

Diseases

Insect

Bird

Over maturity

Blemishes

Latent damage

Improper picking

Dropping

Dumping from harvest container

Yield

Cooler Anticipated price

Field conditions

Processor demand Early morning

Mechanical damage

Accuracy of selection

Time of day

Pulp temperature at harvest

Machine

Human Acceptable

Unacceptable

QUALITY

Crop choice Capital intensive Cropping patterns Labour required Working conditions Rapid harvest potential

Special breeding

improved

Less Must be trained or skilled

Easiest crop

Already machine harvested

Robotics ?

Not easily damaged

Tubers

Root crops Nuts

Perennial crops - damage

Processing – not handling harvest Obsolescence Social impact of low labour requirements

Processing Tomatoes Corn

Potatoes

Belt conveyors Platforms Moveable worker positions

Accuracy

Damage

Harvest rate

Maturity Grading Multiple harvest

Minimal

Hire more workers

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Integrated Approach to

Handling

Guidelines • How do preharvest cultural factors

affect consumer acceptance? • How does storage at non-optimal

conditions affect quality and consumer acceptance?

• Are handlers who adopt new

methods properly rewarded for their improvements?

Quality Management • Operations Research • Application of Technology and

Engineering • Clearer spec of quality and packing ,

value, consumer perspectives • Preharvest factors = variability in quality

and storage • Mean to predict mathematically

(modelling systems) period of optimal marketability – to specific handling conditions

Food Safety • Agricultural chemicals • Cosmetic appearance • Alternative methods, e.g. organic • Pathogens, e.g. E.coli species • Listeria monocytogenes (refrigeration.

Latent damage • Early detection important • Lower quality increased cost of

production (transportation and sorting add cost)

• Damage incurred at one step but not apparent until later step. o Bruising o Quiescent infections o Physiological disorders o Postharvest stress disorders,

e.g. chilling injury

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TRANSPORTATION FROM FIELD In field

Packhouse

Special breeding

Sellers

Wholesale buyers

Customer

Resistance - mechanical

damage - insect/disease

damage

Harvest - uniform

maturity - once-over

harvest

Appearance

Firmness

Flavour

Appearance

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TRANSPORTATION FROM FIELD

(Kadir) Compression

- Over filled bins - Bottom layers - Shallower bin

Bounced

BRUISING

Field container - wooden – vented – cooling

– smooth surface - plastic liners - drop height important

(Table 6.2, pp31)

Picking container Fruit type = container type

- plastic bucket – softer fruit

- bottom dump – less pot for compression damage

- delicate – pack directly from bucket (peaches)

- very soft delicate – pick into package, e.g. strawberries

1. Avoid extended forklift movement 2. minimise rough handling during loading 3. grade farm/orchard track – keep smooth 4. avid uneven/rough public roads 5. restrict transportation speeds to minimize

free movement of front (vibration) 6. use suspension systems – air shocks best. 7. reduce vehicle tyre pressure 8. plastic liners – bubble wrap – bubbles out –

minimise damage 9. top bin pads for long trips – use of shrouds.

Bin dropped Impact

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PACKING HOUSE OPERATION

(1) Sorting

Economics

Design & Operation of sorting equipment • Optimising

o Accuracy o Sorting

• Evaluation o Sorter productivity o Quality

• Space o Size

• Variable flow o Translation speed o Product loading

• View product o Sorter position o Lighting o Location of reject

chutes and conveyors • Worker comfort • Product injury • Training/supervision

Analysis of sorting operations • performance • modelling • empirical model • signal detection theory

Marketing factors • producer • wholesaler • retailers/distributors • customer • price quality

Sorting terminology • Separation (removal of non-useable

material) • Uniform size (free of insects, blemishes,

diseases) • Maturity (firmness, damage levels) • Sorting (segregation, marketable, quality

categories) o Mechanical (colour, sizes o Manual (visual, tactical)

• Graders – sorting line, not graders (3rd party inspectors e.g. ENZA, meet classification, online, off-line.

• Sample inspection (Q.C.)

1

Visual perception • Brightness • Product presentation • Vision difficulties • Concentration for long

periods

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PACKING HOUSE OPERATION (A)

2 Fruit sizing • Colour • Image sizers • Weight and/or size 3

Fruit selection • Capacity • Accuracy • Injury Adjustment ease • Incoming fruit change • Adjust fruit diversion patterns • Ease: cleaning, maintenance

4

Special treatments • Presizing • Cleaning and washing • Waxing/coating • Disease control treatment

OPERATION: Monday: (Frank Bollen, Prussia & Lidrow)

“To transform the highly variable product received from the harvest operation into uniform lots of product for shipments that comply with the requirements of the buyer.”

Wednesday/Thursday - Packaging

MECHANICAL VOLUME-FILL TIGHT FILL

5

PACKING FRUIT • Volume fill packing

system • Packaging material

o Delivery o Removal when

full/packed o QC check

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PACKING HOUSE OPERATION (B)

MECHANICAL • Volume fill • Tight fill

HAND PACKING • Attractive pack • Fixed count (even size) • Immobilization (lateral

tightness)

PURPOSE OF PACKING • Immobilzed

(vibration) • Cushioned (shock)

PACKING LINE • Minimize fruit damage

(padding) • Avoid fruit accumulation • Final sort (QA/QC check • Packaging material

(delivery, removal when full/packed)

• Avoid bottlenecks.

PACKING FRUIT • Volume fill • Tight fill

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SORT

SIZING

AUTO FILLER

PACKAGING

INSPECTION

MARKING

VIBRATION (if req’d)

CLOSING

PALLETING (automatic)

STORAGE

PACKAGING LIDS

TOP PADS (if req’d)

MECHANICAL PACKERS

DROP HEIGHT • Minimized • Shock damage • Major problem

HIGH SPEED • Large volumes • Sorted, graded

fruit required

DELIVER CAREFULLY SORTED & SIZED FRUIT AND PACKAGING • Inspection • Marking • Top padding (closing operation)

VOLUME FILL • Weight as approximation of

volume • Check weights (manual,

automatic) TIGHT FILL • Immobilisation • Without compression • Bruising • Top padding • Tightly fasten lid

PLACE PACKING SYSTEMS • Citrus • Sized fruit • Pack pattern • Rubber/plastic cups

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COOLING METHODS

FIELD HEAT

SUMMER • Rapid cooling and temperature

control o Successful marketing

• Cooling and cold storage requiring different

• Cooling efficiency • Modelling systems TEMPERATURE

PROTECTION • Shade, natural, shade

clothe (silver to reflect) • Prevent warming • Sun scald

RAPID TRANSPORTATION TO PACKHOUSE • Covers

o Silver to reflect o Light colour

PRE-GRADING AND PACKAGING POST-GRADING AND PACKAGING

SELECTION

PRODUCT

limitations mix Temperature req.

OPERATING COSTS

OTHER CONSIDERATIONS

Energy costs

Tradition

ROOM COOLING • Cooling jets • Cooling bays FORCED AIR COOLING • Forced air tunnel • Cold wall • Serpentine cooling • Forced air evaporative

cooling • Container venting HYDRO-COOLING PACKAGE-LANG VACUUM COOLING COOLING BEFORE PAKAGING

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ROOM COOLING

LONG ?? PRODUCE • Common

ADVANTAGE • Cooling and storage in

the same room (minimises transfers)

DISADVANTAGE • Too slow (most

commodities) • More space than

required (good storage)

• Excessive water loss possible

COOLING BAYS • Cooling • Storage

COOLING BAYS • Slow heat removal

STORAGE SPACE MANAGEMENT

WELL VENTILATED CONTAINERS

AIR FLOW • 60 tp 120 m/min

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FORCE-AIR COOLING

Wide range produce

Forced air movement through containers

Slight pressure gradient forces movement

H2O loss prevented by high % RH

Bins

Volume of air

Forced air tunnel (Fig 8.2)

Cold wait (Figs 8.4, 8.5)

Serpentine (Figs 8.6, 8.7)

Forced air evaporative cooling

(Fig. 8.8)

Container renting Req’d SA

Forced air evaporative cooling (Fig. 8.8)

2-3 degrees above outside wet bulb temperature and

% rH + 90%

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HYDRO COOLING

Use of cold water

Advantages • no water loss • quick cooling • efficient heat transfer

Disadvantage • cooling packed produce

• container to pickup • clean

H2O loss prevented by high % rH

Bins

Volume of air

Shower type • 600 – 1000 L/min/m2 SA

(L/min-1.m-2) • low level chlorine

(1 – 2 ppm residual) • produce tolerance

Mechanical water cooling

Cooling times 10 min to 1 hour

Inline cooling • cherries, small fruit

Flume cooling hydro • conveying • cooling

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PACKAGING ATMOSPHERIC MODIFICATION

O2 CONTROL • Recycling/purge

generator • Catalytic burners ⇒

N2 purge liquid N2

MEMBRANE SYSTEMS

CO2 CONTROL • Gases CO2 – gas

cylinders • CO2 scrubbers (lime) –

sodium hydroxide, water, activated carbon, brine, molecular sieve

ACTIVATED ND BROMINATED CHARCOAL • Potassium permanganate • Re,pved C2H4

ETHYLENE REMOVAL

CO ADDITION

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O2

Substrate End product

Starch CO2

Sugars H2O

Organic acids

Amino acids O2H2

Prolin Volatile

Pectin compound Heat

COMMODITY

PACKAGE

STORAGE ROOM/TRANSIT VEHICLE

MAN H2O

N2 78.1%

O2 20.9%

CO2 0.03%

C2H2 plus OTHER

VOLATILES

HEAT

- commodity generated - or passive ACTIVE MODIFIED ATM

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CA/MA STORAGE

ADVANTAGES

DISADVANTAGES

RETART SENESCENCE Slows: Respiration Ethylene production Softening Compositional changes Biochemical Physiological

REDUCTION ETHYLENE SENSITIVITY O2 < 8% and/or CO2 > 1%

PHYSIOLOGICAL DISORDERS Chilling injury

POSTHARVEST PATHOGENS 10 – 75% CO2 Inhibit Botrytis rot on Strawberries Cherries Insects

INSECT CONTROL

DECAY SUSCEPTIBILITY INCR Low O2 damage

STIMULATION Sprouting, e.g. potato –

roots tubers

OFF FLAVOURS/ODOURS Anaerobic Respiration Very low O2

RETARDATION Periderm development

INITIATION/AGGRAVATION Physiological disorders: Blackout – potatoes Brown stain – lettuce Brown heart – apple/pear

IRREGULAR RIPENING (pears, tomatoes) O2 < 2% CO2 > 5%

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