Slide 1: Presentation 3.2 Fresh Fruit and Vegetables Quality and Safety
Maintenance and Enhancement during
the Post-harvest Chain Section III Slide 2: Presentation 3.2 but, the quality of a product
is maintained and enhanced during
its harvest and post-harvest management. quality products are produced
in the fields! Slide 3: Presentation 3.2 Product quality at harvesting Slide 4: Presentation 3.2 Product quality after improper mechanical grading process. Slide 5: Presentation 3.2 Now it is waste...how many opportunities
have been lost! Slide 6: Presentation 3.2 Product quality maintenance (reduce loses)
Generate product added value
Generate market opportunities Principles of postharvest management of FFV Slide 7: Presentation 3.2 Product loses.
(Quality decay/physical loses).
High costs and low profits.
Loss of market opportunities.
Low competitiveness. Inappropriate post-harvest handling Slide 8: Presentation 3.2 Key processes during the
post-harvest- life :
Maturity process. Fruits and vegetables as PERISHABLE products Slide 9: 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 non-climacteric. Slide 10: Presentation 3.2 Respiración Climatérica : Respiración Climatérica time Respiration (mg CO2/Kg./Hr) 180
0 Cherimoya Mango Tomate Prickly pear Slide 12: Strawberry Grape Cherry Lemon Time 30
0 Respiration (mg CO2/Kg./Hr) Slide 13: CLIMACTERIC
Pineapple Slide 14: Respiration
Very High Rep. Rhythm .
5 - 10 mg
10 - 20 mg
20 - 40 mg
40 - 60 mg PRODUCT
Sugar beet, garlic, onion,
cucumber, mango, tomato.
spinach, parsley, sweet
Corn. Slide 15: PERISHABILITY
Very low POTENTIAL LIFE
< 2 weeks
2 - 4 weeks
4 - 8 weeks
8 - 16 weeks
> 16 weeks PRODUCTS
nuts, dried fruits. Slide 16: Presentation 3.2 Factors affecting the respiration rates: External:
mechanical damage and product’s sanitary condition.
atmosphere composition (< Oxygen and CO2< respiration; > ethylene > respiration).
physical barriers (waxes, plastic films, etc.) Slide 17: the temperature - affects the degree of response/
severity of mechanical damage.
Compromise natural barriers -increasing
water loses and pathogenic infections. Impact Respiration Time Ethylene Mechanical damage during
the postharvest chain Slide 18: Presentation 3.2 Slide 19: Presentation 3.2 Slide 20: At temperatures above the optimum, the rate of deterioration increases 2 to 3 fold for every 10ºC rise in temperature.
High temperature-increases the transpiration rate. Respiratory rhythm Time 10ºC 20ºC 30ºC Slide 21: Presentation 3.2 Loss of water, as vapor, from the product’s area exposed to the air, throughout the cuticle, lenticels, stomas, etc. It depends on:
species and variety.
type of tissue.
integrity and sanitary product condition. Slide 22: 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). Slide 23: Presentation 3.2 Ethylene production 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 ) Slide 24: Presentation 3.2 Ripening Process 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 Slide 25: STRAWBERRY –EXTERNAL COLOUR CHANGES. Slide 26: MANGO-INTERNAL COLOUR CHANGES Slide 27: 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. Slide 28: Unripe Ripened Interior 100% 0% Exterior 100% 0% Natural fungistatic compounds. Slide 29: Presentation 3.2 Quality maintenance Post-harvest Avoid the negative effect of external factors To reduce and delay the action of the internal factors that are responsible for product deterioration Slide 30: Presentation 3.2 Temperature control.
Product protection from sun heat (full sunlight) after harvesting.
Pre-cooling treatments to remove field heat.
Maintaining the cold chain. Reducing product respiration rates Slide 31: 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. Slide 32: Presentation 3.2 Slide 33: Presentation 3.2 Temperatures above or below the
optimal range, can cause product
deterioration due to:
Heat injury. TºC Slide 34: 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. Freezing: Slide 35: Presentation 3.2 Chilling Injury:
Some commodities (mainly tropical and sub-
tropical) respond unfavorably to storage at
low temperatures well above their freezing
points, temperatures called the chilling
threshold temperature or lowest safe
temperature. Slide 36: Presentation 3.2 Chilling injury. Slide 37: 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. Slide 38: Presentation 3.2 Objective: to remove the field heat.
Movement of the caloric energy from the product to the cooling substance. Cooling Slide 39: Presentation 3.2 Cooling methods Slide 40: Presentation 3.2 Commercial cooling reaches up to 7/8 the final temperature.
First hours are crucial.
Additive effect of low temperatures. Time Temp. Cooling speed Slide 41: Presentation 3.2 Storage and refrigerated transport well designed and adequately equipped.
with adequate and well-positioned doors for loading and unloading.
allow effective distribution of refrigerated air.
allow monitoring and temperature control. Cooling rooms and refrigerated vehicles…. Slide 42: Presentation 3.2 Slide 43: Presentation 3.2 Slide 44: 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). Storage and refrigerated transport Slide 45: Presentation 3.2 transit vehicles must be cooled before loading the commodity.
when mixing several products: product’s ethylene and chilling injury sensibility must be considered.
appropriate packing (air circulation and reducing mechanical damage) Storage and refrigerated transport Slide 46: Presentation 3.2 Slide 47: 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. reducing
transpiration rates Slide 48: Presentation 3.2 Fruits: 85-95% of RH.
Dry products: onion and pumpkin. 70-75% de RH.
Root vegetables: carrot, radish. 95-100% RH. RH ranges Slide 49: Presentation 3.2 reducing transpiration rates 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. Slide 50: 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. reducing transpiration rates Slide 51: Air in the internal
Cavity Wax layer restricts
the gases interchange. waxing fruits Slide 52: Presentation 3.2 Wetting floors in storage rooms.
Adding crushed ice in shipping containers.
Sprinkling produce with sanitized, clean water during retail marketing of the product. reducing
transpiration rates Slide 53: Presentation 3.2 avoiding sources of ethylene close to the product storage areas.
applications of 1-Methylcyclopropene (1-MCP)- ethylene action inhibitor, commercially approved on July 2002 in apples, apricots, avocados, kiwifruit, mangoes, nectarine, papayas, peaches, pears, persimmons, plums, and tomatoes. Ethylene Reducing
ethylene damage Slide 54: Presentation 3.2 Air ventilation of storage rooms.
Avoid mixing ethylene sensitive products with those non sensitive to ethylene, during storage and transport. Reducing
ethylene damage Slide 55: 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. Senescence delaying senescence… Slide 56: Presentation 3.2 Irradiation.
Chemical: methyl bromide, phosphine, hydrogen cyanide)
Cold treatments (Low temperatures)
Combination of the previous. Insects Treatments for insect control Slide 57: 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.
. Insects Treatments for insect control ... Slide 58: Presentation 3.2 manipulation of the environment
around the produce Modified and controlled atmosphere storage Slide 59: Presentation 3.2 Manipulation of the environment
around the produce Slide 60: Modify the concentration of gases in the produce packing.
Reduce respiration rate.
Reduce ethylene action.
Delay ripening & senescence.
Increase product’s shelf life. O2 CO2 O2 CO2 21% O2 0.035% CO2 Modified atmosphere
(MAP) Slide 61: 21% Oxigene
0.35% CO2 2% O2
1% CO2 Filters Cold room
0ºC Apples, as any living entities..breath Controlled Atmosphere (CA) Slide 62: Presentation 3.2 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.
Dynamic atmospheres- O2 y CO2 are modified through monitoring of produce quality attributes such as: ethanol concentration and chlorophyll fluorescence. Manipulation of the environment
around the produce Slide 63: 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. CA during product transport Slide 64: 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. Modified atmospheres Slide 65: Presentation 3.2 Slide 66: Plastic or cardboard
box Polymeric film-
perforated one Apples treated
with TBZ Storage temperature-0.5oC Storage protocol Slide 67: Presentation 3.2 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. Commercial use Slide 68: Presentation 3.2 Genetic factors, production of hybrids and varieties
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. Preharvest factors affecting the quality
of fresh fruits and vegetables. Slide 69: 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. Preharvest factors affecting the quality
of fresh fruits and vegetables. Slide 70: Presentation 3.2 Cultural practices:
Nutritional conditions: Calcium related with long post-harvest life; high Nitrogen related with shorter post-harvest 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. Preharvest factors affecting the quality
of fresh fruits and vegetables. Slide 71: 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. Hazards associatted with produce quality Slide 72: Presentation 3.2 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. Causes....factors favoring quality decay. Primary damages are the result of inappropriate
technologies and handling during the post-harvest chain: Slide 73: 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. Causes....factors favoring quality decay. Slide 74: Presentation 3.2 Post-harvest procedures Other treatments Pre-cooling Drying Selection,
cleaning and disinfection Reception Grading Packing and packaging Storage Transport Harvesting Slide 75: Presentation 3.2 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). Harvesting Associated hazards Slide 76: 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. Slide 77: Presentation 3.2 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. Produce reception Associated hazards Slide 78: Presentation 3.2 Slide 79: Presentation 3.2 Possible Hazards associated Pre-cooling Slide 80: Presentation 3.2 Objective: Removing impurities from the product. Slide 81: Presentation 3.2 Possible Hazards associated Slide 82: Presentation 3.2 Associated Hazards Grading Slide 84: Presentation 3.2 Associated Hazards Slide 85: Presentation 3.2 Packing and packaging Associated Hazards Slide 86: Presentation 3.2 Storage 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). Associated Hazards: mechanical, physical, biological damages. Slide 87: Presentation 3.2 Transport 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). Slide 88: Presentation 3.2 Slide 89: Presentation 3.2 Slide 90: Presentation 3.2 Efficiency of the loading and unloading systems Slide 91: Presentation 3.2 Other Post-harvest treatments 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). Slide 92: Presentation 3.2 Final Considerations the selection of “the best technologies” to be applied, among a range of available post-harvest technologies, should take into account: the product characteristics, the market distance and requirements, and the social and economical conditions of the actors involved. Slide 93: Presentation 3.2 Cold chain Temporal
storage Transport 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
Practice first in first out rotation.
Ship to market as soon as possible. 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. Slide 94: Presentation 3.2 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. Final Considerations Slide 95: 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
Proper harvesting time, avoid direct sun light,
proper handling, proper ventilation, etc. Final Considerations Slide 96: 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. Final considerations Slide 97: Presentation 3.2 Photographic Material :
Archives FAO. 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.
Tel.: +39 06 57053308
Fax.: +39 06 570 54593/53152