Presentation 3.2
Presentation 3.2
Product quality at
harvesting
Presentation 3.2
Presentation 3.2
Product quality after
improper mechanical
grading process.
Presentation 3.2
• Product quality maintenance
(reduce loses)
• Generate product added value
• Generate market opportunities
Presentation 3.2

Product loses.
(Quality decay/physical loses).
 High costs and low profits.
 Loss of market opportunities.
 Low competitiveness.
Presentation 3.2
Key processes during the
post-harvest- life :
•
•
•
•
Respiration .
Transpiration .
Ethylene production.
Maturity process.
Presentation 3.2
Factors affecting the respiration rate of FFV:
Internal:
 Type of tissue or organ: Leaves > fruits>
roots.
 Product size: bigger size< respiration rate.
 Stages of development: young leaves
>respiration. In fruits will depend on their
classification as climacteric or nonclimacteric.
Presentation 3.2
Presentation 3.2
Respiración Climatérica
180
160
140
120
100
80
60
40
20
0
Cherimoya
Mango
Prickly pear
Tomate
time
30
20
Strawberry
Grape
10
Cherry
Lemon
0
Time
CLIMACTERIC
NO-CLIMACTERIC
Avocado
Mango
Guava
Plantain
Banana
Papaya
Apple
Carambola
Egg-Plant
Lemon
Orange
Watermelon
Pineapple
Respiration
rate
Low
Moderate
High
Very High
Rep. Rhythm .
Mg CO2/Kg./Hr
5 - 10 mg
PRODUCT
Sugar beet, garlic, onion,
watermelon, citrus.
10 - 20 mg
Cabbage, carrot,
cucumber, mango, tomato.
20 - 40 mg
Avocado, cauliflower,
lettuce, strawberry.
40 - 60 mg
Artichoke, broccoli,
spinach, parsley, sweet
Corn.
PERISHABILITY POTENTIAL LIFE
INDEX
(WEEKS)
Very high
< 2 weeks
High
2 - 4 weeks
Moderate
4 - 8 weeks
Low
8 - 16 weeks
Very low
> 16 weeks
PRODUCTS
broccoli, cauliflower,
blackberry, strawberry
avocado, pineapple,
celery, tomato
lemon, watermelon
mango, potato,
onion, apple,
garlic, pear
nuts, dried fruits.
Factors affecting the respiration rates:
External:
 mechanical damage and product’s sanitary
condition.
 temperature.
 atmosphere composition (< Oxygen and
CO2< respiration; > ethylene > respiration).
 physical barriers (waxes, plastic films, etc.)
Presentation 3.2
• the temperature - affects the degree of response/
severity of mechanical damage.
• Compromise natural barriers -increasing
water loses and pathogenic infections.
Impact
Respiration
Ethylene
Time
Presentation 3.2
Presentation 3.2
• At temperatures
30ºC
above the optimum,
the rate of
20ºC
deterioration
increases 2 to 3 fold
for every 10ºC rise in
10ºC
temperature.
• High temperatureincreases the
transpiration rate.
Time
 Loss of water, as vapor, from the product’s
area exposed to the air, throughout the cuticle,
lenticels, stomas, etc. It depends on:
Internal factors:
 species and variety.
 type of tissue.
 integrity and sanitary product condition.
Presentation 3.2
External factors:
 Relative Humidity (<RH> transpiration).
 Temperature (> temperature>
transpiration)
 Air movement (increase the transpiration
rate).
 Altitude (higher altitude< transpiration).
 Physical barriers (avoid air contact with the
product-reduce transpiration rate).
Presentation 3.2
 Climacteric fruits are sensitive to ethylene-
produce larger quantities of ethylene in
association with their ripening- (auto catalysis).
 No climacteric fruits produce very small
quantities of ethylene. At high concentration
produce degreening and increase the
metabolism.
 Leafy vegetables are highly sensitive to
Ethylene (withering and yellowing )
Presentation 3.2
 Physiological process that occur at the cellular
level. After finishing the anabolic process, a series
of catalytic reactions start –degradation of:
chlorophyll, aromas, organelles and finally causing
cellular collapse/death.
Post-harvest technology: to delay
as long as possible, the tissue
disintegration/senescence phase
Presentation 3.2
STRAWBERRY –EXTERNAL COLOUR CHANGES.
MANGO-INTERNAL COLOUR CHANGES
• Loss of chlorophyll (undesirable in veg.)
• Production of carotenoids and
antocianines.
• Starches conversion into sugars.
• Changes in organic acids, proteins and
fats.
• Reduction in tannins and fungistatic
compounds.
100%
100%
0%
Unripe
0%
Ripened
Exterior
Interior
To reduce and delay the
action of the internal
factors that are responsible
for product deterioration
Presentation 3.2
Avoid the negative
effect of external
factors
Temperature control.
• Product protection from sun heat (full
sunlight) after harvesting.
• Pre-cooling treatments to remove field
heat.
• Refrigeration.
• Maintaining the cold chain.
Presentation 3.2
• Key factor affecting product deterioration rate.
• is the most effective tool for extending the
shelf life of fresh horticultural commodities.
• Key effect on spores germination and
pathogenic growth.
Presentation 3.2
Effect of temperature on deterioration rate of a non-chilling sensitive
commodity
Temperature
(°C)
Assumed Q10*
0
10
3
20
2.5
30
2
40
1.5
Source: Kader & Rolle (2003)
Presentation 3.2
Relative
Relative post- Loss per
velocity of
harvest life
day (%)
deterioration
1
100
1
3
33
3
7.5
13
8
15
7
14
22.5
4
25
Temperatures above or below the
optimal range, can cause product
deterioration due to:
• Freezing.
• Chilling injury.
• Heat injury.
Presentation 3.2
• Freezing point of perishable commodities is
relatively high (ranging from -0.3 ºC y -0.5 º C).
• Freezing produces an immediate collapse of
tissues and total loss of cellular integrity.
• A result of inadequate design of refrigerator or
failure of thermostats.
Presentation 3.2
Chilling Injury:
Some commodities (mainly tropical and subtropical) respond unfavorably to storage at
low temperatures well above their freezing
points, temperatures called the chilling
threshold temperature or lowest safe
temperature.
Presentation 3.2
Classification of chilling-sensitive fruits and vegetables according to their lowest safe temperature for
transport and storage
Lowest safe
temperature
Commodities
(°C)
3 Asparagus, cranberry, jujube
4 Cantaloupe, certain apple cultivars (such as McIntosh and Yellow Newton), certain avocado
cultivars (such as Booth and Lula), lychee, potato, tamarillo
5 Cactus pear, cowpeas, durian, feijoa, guava, kumquat, lima bean, longan, mandarin,
orange, pepino
7 Certain avocado cultivars (such as Fuerte and Hass), chayote, okra, olive, pepper,
pineapple, pomegranate, snap bean
10 Carambola, cucumber, eggplant, grapefruit, lime, mango (ripe), melons (casaba, crenshaw,
honeydew, persian), papaya, passion fruit, plantain, rambutan, squash (soft rind), taro,
tomato (ripe), watermelon
13 Banana, breadfruit, cherimoya, ginger, jackfruits, jicama, lemon, mango (mature-green),
mangosteen, pumpkin and hard-rind squash, sapotes, sweet potato, tomato (maturegreen), yam
Source: Kader & Rolle (2003)
Presentation 3.2
Heat injury:
Direct sources of heat can rapidly heat
tissues to above the thermal death point of
their cells, leading to localized bleaching or
necrosis or general collapse.
Presentation 3.2
Objective: to remove the field heat.
Movement of the caloric energy from the
product to the cooling substance.
Presentation 3.2
Comparison among cooling methods
Cooling method
Cooling times (h)
0.1-0.3
Water contact with
the product
yes
Product moisture loss
(%)
0-0.5
Capital cost
high
0.1-1.0
0.3-2.0
ForcedRoom
air
1.0-10.0 20-100
yes
no
no
0-0.5
low
2.0-4.0
0.1-2.0
medium
low
Energy efficiency
low
Source: Kader & Rolle (2003)
high
Variable
Presentation 3.2
Ice
Hydro
Vacuum
high
no
low
0.1-2.0
low
low
• Commercial cooling
reaches up to 7/8 the
final temperature.
• First hours are
crucial.
• Additive effect of low
temperatures.
Time
Presentation 3.2
Cooling rooms and refrigerated vehicles….
•
•
•
•
well designed and adequately equipped.
resistant floors.
perfectly insulated.
with adequate and well-positioned doors
for loading and unloading.
• allow effective distribution of refrigerated
air.
• allow monitoring and temperature control.
Presentation 3.2
Presentation 3.2
Presentation 3.2
• refrigerated coils surfaces designed to
adequately minimize differences between
the coil and air temperatures.
• proper air spaces between pallets and
room walls to ensure proper air circulation.
• monitoring temperature (product rather
than air temperature).
Presentation 3.2
• transit vehicles must be cooled before
loading the commodity.
• avoid delays.
• when mixing several products: product’s
ethylene and chilling injury sensibility must
be considered.
• appropriate packing (air circulation and
reducing mechanical damage)
Presentation 3.2
Presentation 3.2
Relative humidity management.
Is the moisture content (as water vapor) of the
atmosphere, expressed as a percentage of the amount of
moisture that can be retained by the atmosphere at a
given temperature and pressure without condensation.
RH can influence water loss, decay development,
incidence of physiological disorders, and uniformity of
fruit ripening.
Presentation 3.2
• Fruits: 85-95% of RH.
• Dry products: onion and pumpkin. 70-75%
de RH.
• Root vegetables: carrot, radish. 95-100%
RH.
Presentation 3.2
• Adding moisture (sprays, steam)
• Regulating air movement and ventilation in
relation to the produce load in the cold storage
room.
• Maintaining temperature of the refrigeration
coils within about 1ºC of the air temperature.
• Providing moisture barriers that insulate walls of
storage room and transit vehicles.
• Adding polyethylene liners in containers and
using perforated polymeric films for packaging.
Presentation 3.2
•
•
•
•
•
Curing.
Waxes and others surface coatings .
Polymeric films for packing.
Avoiding physical injuries.
Adding water to those commodities that
tolerate misting with water.
Presentation 3.2
Wax layer restricts
the gases interchange.
Air in the internal
Cavity
• Wetting floors in storage rooms.
• Adding crushed ice in shipping containers.
• Sprinkling produce with sanitized, clean
water during retail marketing of the
product.
Presentation 3.2
• avoiding sources of ethylene close to the
product storage areas.
• applications of 1-Methylcyclopropene (1MCP)- ethylene action inhibitor,
commercially approved on July 2002 in
apples, apricots, avocados, kiwifruit,
mangoes, nectarine, papayas, peaches,
pears, persimmons, plums, and tomatoes.
Presentation 3.2
• Air ventilation of storage rooms.
• Avoid mixing ethylene sensitive products
with those non sensitive to ethylene,
during storage and transport.
Presentation 3.2
• Curing.
• Heat treatments i.e.. dipping mangoes, 5 minutes to 50ºC
water to reduce anthracnose development).
• Post-harvest pesticides (i.e.. imazalil, thiabendazole).
• Biological control agents, (i.e.. Bio-save-pseudomonas
syringae y Aspire-Candida oleophila) in citrus fruits.
• Growth Regulators as Gibberellic acid to delay senescence in
citrus fruits.
• 15-20% of CO2 in the air or 5% O2 in strawberries,
pomegranates, figs, etc.
• SO2 fumigation (100 ppm/1 hour) in grapes.
Presentation 3.2
• Irradiation.
• Quarantine treatments:
– Chemical: methyl bromide, phosphine,
hydrogen cyanide)
– Cold treatments (Low temperatures)
– Heat treatments
– Combination of the previous.
Presentation 3.2
Irradiation.
• Dose varies in accordance with the species and
its stage of development.
• Doses of 250 Gy has been approved for:
lychees, mangoes and papayas in USA for
control of fruit fly.
• At doses above 250 Gy and up to1000 Gy some
commodities could present damages.
.
Presentation 3.2
Modified and controlled atmosphere storage
Presentation 3.2
Classification of horticultural crops according to their controlled atmosphere storage potential at optimum
temperatures and relative humidifies
Range of storage
Commodity
duration (months)
More than 12
Almond, Brazil nut, cashew, filbert, macadamia, pecan, pistachio, walnut, dried fruits and
vegetables
6-12
Some cultivars of apples and European pears
3-6
Cabbage, Chinese cabbage, kiwifruit, persimmon, pomegranate, some cultivars of Asian
pears
Avocado, banana, cherry, grape (no SO2), mango, olive, onion (sweet cultivars), some
cultivars of nectarine, peach and plum, tomato (mature-green)
Asparagus, broccoli, cane berries, fig, lettuce, muskmelons, papaya, pineapple, strawberry,
sweet corn; fresh-cut fruits and vegetables; some cut flowers
1-3
<1
Presentation 3.2
21% O2
O2
0.035% CO2 • Modify the concentration
CO2
O2
CO2
•
•
•
•
of gases in the produce
packing.
Reduce respiration rate.
Reduce ethylene action.
Delay ripening &
senescence.
Increase product’s shelf
life.
Apples, as any living entities..breath
Cold room
0ºC
2% O2
1% CO2
21% Oxigene
0.35% CO2
Filters
Innovations:
• Creation of nitrogen-on demand, using systems of
Membrane systems or sieve beds.
• Use of low oxygen concentrations (0.7 a 1.5%) and
monitoring of such concentrations.
• Ethylene free CA.
• Programmed atmosphere.
• Dynamic atmospheres- O2 y CO2 are modified through
monitoring of produce quality attributes such as: ethanol
concentration and chlorophyll fluorescence.
Presentation 3.2
• Banana can be harvested at a later stage.
• In avocados CA allows the use of lower
temperatures than the conventional ones
and reduces chilling injury.
• In combination with temperature control,
CA is used as quarantine treatment for the
control of several insects.
Presentation 3.2
• Use of MAP during packing is highly
increasing.
• Usually designed to maintain 2% - 5% of
O2 and 8% - 12% of CO2, extend shelf life
of fresh-cut fruits and vegetables.
Presentation 3.2
Presentation 3.2
Apples treated
with TBZ
Polymeric filmperforated one
Plastic or cardboard
box
Storage temperature-0.5oC
• CA is used for transporting and storage of
apples, pears, less used in kiwifruits,
avocados, nuts, dry fruits and persimmon.
• MA- for long distance transport is used in
mangoes, apples, bananas, avocados,
plums ,strawberries, blackberries,
peaches, figs, nectarines.
Presentation 3.2
Genetic factors, production of hybrids and varieties
with….
• High contents of carotenes and Vitamin A
(tomatoes, onions and carrots).
• Long post-harvest life (tomatoes and onions).
• High content of sugars (melon).
• High content of ascorbic acid (pineapple).
• In the future…Biotechnology will perhaps allow
the introduction of resistance to physiological
disorders and/or pathogens associated to quality
decay.
Presentation 3.2
Climatic conditions:
• Temperature and light intensity can
influence the content of ascorbic acid,
carotenes, riboflavin, thiamine and
flavonoids.
• Rainfall affects the water supply and the
susceptibility of plant organs to mechanical
damage and decay.
Presentation 3.2
Cultural practices:
• Nutritional conditions: Calcium related with long postharvest life; high Nitrogen related with shorter postharvest life due to high susceptibility to mechanical
damage, physiological disorders and decay.
• Several physiological disorders are associated with
nutritional deficiencies.
• Water stress (from severe to moderate) is related with
irregular ripening, reduced fruit size, increase Total Solid
Soluble contents and acidity.
• Water excess increases the susceptibility to physical
damage in some products.
Presentation 3.2
Primary damages…perceptible, what is easily identified
by the consumer.
• Biological: pest and diseases.
• Chemical: visible external contamination with
pesticides and chemical products; toxics and
unpleasant flavors produced by pathogens, etc.
• Mechanical: injures, cuts, bruises, grazes, drops,
scrapings, shatters during harvesting, etc.
• Physical: heating, freeze, freezing, water loss.
• Physiological: sprouting, rooting, senescence,
and changes caused by transpiration and
respiration.
Presentation 3.2
Primary damages are the result of inappropriate
technologies and handling during the post-harvest chain:
• inappropriate process of drying.
• inappropriate Infrastructure for produce
packaging and storage.
• improper transport conditions.
• lack of planning (i.e.. harvesting).
• delays, improper conditions during
distribution and marketing.
Presentation 3.2
• during periods of oversupply-poor handling
increase.
• poor or inappropriate harvesting techniques.
• poor produce handling.
• damages originated during handling and
transport.
• delays during the distribution process.
• loses of weight and water.
Presentation 3.2
Harvesting
Reception
Other
treatments
Packing and
packaging
Presentation 3.2
Pre-cooling
Selection,
cleaning and
disinfection
Grading
Drying
Storage
Transport
Harvesting
Associated hazards
• inappropriate maturity at harvest (over ripening increases
sensitivity to quality decay ; immature fruits market rejection).
• inappropriate harvest technique (mechanical damages-physical
injuries).
• climatic conditions at harvesting (free water, exposition of
product to direct sun light )
• harvesting wet products (increase sensitivity to quality decay)
• inappropriate harvesting recipes/containers ( physical injuries).
Presentation 3.2
Recommendations
• training personnel on optimum maturity indices.
• Application of appropriate maturity indices based on: external
quality color, consistence, phenological stage, etc.
• Harvesting time: early in the morning or late in the afternoon
in order to minimize the sun effect.
• Optimizing harvesting recipes/containers (size, materials,
height, number of produce layers, conditions, etc. )
• protection of product of direct sun intensity.
Presentation 3.2
Produce
reception
Associated hazards
• uncovered areas (direct exposition of products to sun light and
adverse climatic conditions)
• inappropriate handling of the product during loading and
unloading.
• inappropriate product heaping (mechanical damages).
• delays in the operations (if conditions are inappropriate they can
generate increasing product temperature and quality decay)
• lack of planning during harvesting (increase delays in the
operations).
• no methods applied to remove field heat or use of inappropriate
ones.
Presentation 3.2
Presentation 3.2
Pre-cooling
Possible Hazards associated
Definir actores/roles/
Expectativas.
If the methods of pre-cooling are inappropriate, they
can:
• produce dehydration of the product (i.e.. high speed
of cooling air)
• tissue damage –i.e. as result of inappropriate packing
-product contact with ice.
• produce quality decay caused by sensitivity of the
product to water exposition.
• accelerate quality decay by accumulation of water in
some areas of the product (between leaves and calyx)
Presentation 3.2
Cleaning and
disinfection
Definir actores/roles/
Expectativas.
Objective: Removing impurities
from the product.
Definir actores/roles/
Expectativas.
Washing methods:
Web methods:
• Immersion (product floating).
• Spraying .
Dried methods:
• Brushing.
• Inhalation/aspirate.
Presentation 3.2
Cleaning and
disinfection
Definir actores/roles/
Expectativas.
Definir actores/roles/
Expectativas.
Possible Hazards associated
• product water sensitivity.
• poor water quality.
• mechanical damage (inappropriate conditions of
brushes, etc).
• water accumulation in the product can cause product
quality decay.
Presentation 3.2
Grading
Associated Hazards
Mechanical damages by vibration, impact/hitting, compression, etc.
caused either by poor handling or inappropriate equipment
maintenance and design.
Grading methods: by size, weight, color, etc.
Presentation 3.2
Packing and
packaging
Associated Hazards
• poor packing design (reduces efficiency and increases
the risk of mechanical and biological hazards).
• improper packing (lack of ventilation, low material
resistance, sharp and wrinkled surfaces, etc.).
• Over packing (many product layers).
Definir actores/roles/
Expectativas.
Presentation 3.2
Packing and
packaging
Associated Hazards
• Inappropriate pile up during packing.
• packing products with different degree of maturity.
• mechanical damages caused by personnel or improper
design of mechanical grading machines.
• Problems regarding over-handling of products and
inappropriate process flows during post-harvest handling.
Definir actores/roles/
Expectativas.
Presentation 3.2
Storage
Associated Hazards:
mechanical, physical,
biological damages.
• Inappropriate design of cooling rooms.
• Poor or lack of equipment maintenance and cleaning programmes.
• Lack of control of temperature and Relative Humidity conditions.
• Lack of control on personnel entrance to the cooling rooms.
• Poor or lack of cooling rooms cleaning programmes.
• Inappropriate distribution/location of the product inside the cooling
room (reducing air circulation).
Presentation 3.2
Transport
Associated hazards: chemical,
biological, mechanical damages.
• Bad conditions of the vehicles tents/covers.
• Poor cushioning systems of the vehicles.
• Inappropriate systems of loading and unloading.
• Uncovered vehicles, expose the product to the negative
effect of the environmental conditions.
• poor control of temperature and relative humidity in the
refrigerated transport systems.
• Inappropriate systems of packing (p.e. in bulk).
Presentation 3.2
Definir actores/roles/
Expectativas.
INNOVATIONS IN THE TRANSPORT
Presentation 3.2
Definir actores/roles/
Expectativas.
Loading and unloading systems
efficiency
Presentation 3.2
Efficiency of the loading and unloading systems
Presentation 3.2
Other Postharvest
treatments
Associated hazards: increase
Definir actores/roles/
product’s susceptibility to
Expectativas.
biological, mechanical damages
and quality decay.
• Improper handling during treatment application.
• Inappropriate application of the treatments (p.e.
temperatures above or below the optimum
recommended).
• Improper RH conditions.
• Poor equipment maintenance and cleaning.
• Doses above the recommended ones (i.e..
irradiation dosages).
Presentation 3.2
• the selection of “the best technologies” to be
applied, among a range of available postharvest technologies, should take into account:
the product characteristics, the market distance
and requirements, and the social and
economical conditions of the actors involved.
Presentation 3.2
To protect the product from direct sun
light.
Quick transport to the packaging.
Minimize delays before pre-cooling.
Uniform product’s cooling.
Store the product at optimum temperature
conditions .
Practice first in first out rotation.
Ship to market as soon as possible.
Presentation 3.2
Use refrigerated loading area.
Cool truck before loading.
Load pallets towards the center of the truck.
Avoid delays during transport.
Monitor product temperature during transport.
• There is not a direct relation between a given
post-harvest technology efficiency and its cost.
Expensive equipment does not always imply
high efficiency, and even the best equipment,
without proper management may have little
utility and poor results. Effective training and
supervision of personnel must be an integral
part of quality and safety assurance programs.
Presentation 3.2
Proper product handling during the post-harvest Chain
relies in understanding the factors that affect the quality
and safety of the product, and the different mechanisms to
minimize their impact. Simple handling practices can have
important impact on product quality and safety
maintenance.
Proper harvesting time, avoid direct sun light,
proper handling, proper ventilation, etc.
Presentation 3.2
Product quality maintenance and enhancing implies:
• To identify the problems (main causes) and their magnitude (quality
and physical loses). Also to identify the opportunities associated to
the post-harvest technologies.
• Search the available solutions to the problems identified, or
mechanisms to take advantage of the opportunities. (training,
application of available technologies, adjustment and validation of
technologies if needed, practical research if need).
• To evaluate the impact of small changes during the post-harvest
chain.
• To train the personnel involved in implementing the changes.
• To identify the problems needing practical research in order to
identify possible solutions.
Presentation 3.2
FOOD AND AGRICULTURE ORGANIZATION OF
THE UNITED NATIONS (FAO)
Food Quality and Standards Service (ESNS)
Food and Nutrition Division
Viale delle Terme di Caracalla
00100 Rome, Italy.
E-mail: food-quality@fao.org
Tel.: +39 06 57053308
Fax.: +39 06 570 54593/53152
http://www.fao.org/
Photographic Material :
Fernando Maul.
Archives FAO.
Presentation 3.2