presentation 3.2 food deterioration and its causes

Presentation 3.2

Food Deterioration and its Causes

• What is food deterioration, and how can food science minimize its effects?

Food deterioration includes:

• changes in organoleptic quality (how something is perceived by a sensory organ)

• nutritional value• food safety• aesthetic appeal• color

• texture

• flavor

To some degree, all foods undergo deterioration after harvest. The role of food science is to minimize negative changes as much as possible.

Presentation 3.2

Product quality at harvesting

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Product quality after improper mechanical

grading process.

Presentation 3.2

LOSS OF HORTICULTURAL CROPS

Loss in quantity and quality between harvest and consumption:

5 - 25% in developed countries

20 - 50% in developing countries

CATEGORIES OF DETERIORATION

any change in the appearance, smell, or taste of a food product that makes it unacceptable to the consumer.

Food DETERIORATION results in economic loss to producers, distributors, and even consumers.

Causes of Food Deterioration

• Phisiology• Microbial spoilage • Chemical reactions can also reduce food quality

– Exposure to air or light (oxidative rancidity)– Reactions caused by enzymes in the food

leading to off-flavors– Other chemical reactions/interactions

• Cold storage temperatures can minimize chemical re

Table 1. Useful ShelfLife at 70 F

• Food Days

• Meat 1 to2

• Fish 1 to 2

• Poultry 1 to 2

• Dried, smoked meat 360+

• Fruits 1 to 7

Table 1. Useful ShelfLife at 70 F

• Food Days

• Leafy vegetables 1 to 2

• Root Crops 7 to 20

• Dried seeds 360 +

The three general categories of food deterioration are:

• Physical• Chemical• Biological • Factors that cause food deterioration

include: light, cold, heat, oxygen, moisture, dryness, other types of radiation, enzymes, microorganisms, time, industrial contaminants and macroorganisms (insects, mice, and so on).

WHAT CAUSES FOOD DETERIORATION?

• Deterioration can be caused by one or more of the following:

• Microorganisms such as bacteria, yeast and molds; • Activity of food enzymes; • Infestations by insects, parasites and rodents; • Inappropriate temperatures during processing and

storage; • Gain or loss of moisture; • Reaction with oxygen; • Light; • Physical stress or abuse; and • Time.

BIOLOGICAL CHANGES CAN INCLUDE

• WILTING

• DISCOLORATION

• SLIME FORMATION/COAGULATION

• OFF-FLAVORS

• OFF-ODORS

• EXCESSIVE MICROBIAL NUMBERS/TOXINS

CHEMICAL CHANGES CAN INCLUDE

• OFF-FLAVORS

• OFF-ODORS

• DISCOLORATION (BROWNING, FADING)

• TEXTURAL CHANGES

• CONTAINER INTERACTIONS

CONTROL OF CHEMICAL CHANGES

• AVOID EXCESSIVE HIGH TEMPERATURES

• AVOID EXPOSURE TO LIGHT• MINIMIZE EXPOSURE TO OXYGEN• PROPER PROCESSING TO

MINIMIZE MAILLARD REACTIONS DURING PROCESSING

Presentation 3.2

Reduce losses:

1. Understand biological en environmental factors involved in deterioration

2. Use postharvest techniques that delay senescence and maintain the best possible quality

BIOLOGICAL FACTORS INVOLVED IN DETERIORATION

1. Respiration

2. Transpiration

3. Growth and development

4.Compositional changes

5. Physiological breakdown

.6.Pathological breakdown

7. Physical damage

Nest of gray mould

ENVIRONMENTAL FACTORS INFLUENCING DETERIORATION

2. Relative humidity

3. Atmosphere composition

4. Ethylene

5. Light

1. Temperature

Leather rot

Rhizopus rot

Presentation 3.2

• Product quality maintenance Product quality maintenance (reduce loses)(reduce loses)

• Generate product added Generate product added value value

Presentation 3.2

Key processes during the

post-harvest- life :

• Respiration .

• Transpiration .

• Maturity process.

Typical life cycle of living tissues

Development/growth (metabolic,biosynthetic reactions)

↓Maturation

↓Ripening

↓Senescence (catabolic, degradative reactions)

↓Deterioration

BIOCHEMICAL REACTIONS OF RESPIRATION

Plants have the ability to utilize energy from sunlight for synthesis of carbohydrates using CO2 and H2O in the air; photosynthesis.

CO2 + H2O + (sunlight) (CH2O)n + O2

Organisms consume carbohydrates and convert them into energy through an enzymatic process called respiration.

C6H12O6 + 6O2 6CO2 + 6H2O + 673 Kcal

Presentation 3.2

Factors affecting the respiration rate of FFV:

Internal: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.

Presentation 3.2

PERISHABILITYINDEX

Very high

High

Moderate

Low

Very low

POTENTIAL LIFEPOTENTIAL LIFE(WEEKS)(WEEKS)

< 2 weeks

2 - 4 weeks

4 - 8 weeks

8 - 16 weeks

> 16 weeks

PRODUCTSPRODUCTS

broccoli, cauliflower,blackberry, strawberryavocado, pineapple,celery, tomatolemon, watermelonmango, potato,onion, apple,garlic, pear

nuts, dried fruits.

Presentation 3.2

Factors affecting the respiration rates:Factors affecting the respiration rates:

External: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

• 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.

Res

pira

tory

rhy

thm

Time

10ºC

20ºC

30ºC

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:

Internal factors:Internal factors:

species and variety. type of tissue.

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External factors:External factors:

Relative Humidity (<RH> transpiration). Temperature (> temperature> transpiration) Altitude (higher altitude< transpiration).

Presentation 3.2

Relative humidity management.Relative humidity management.

Is the moisture content (as water vapor) of theatmosphere, expressed as a percentage of the

amount ofmoisture that can be retained by the atmosphere at agiven temperature

RH can influence water loss, decay development,incidence of physiological disorders, and uniformity offruit ripening.

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.

Air in the internal Cavity

Wax layer restricts the gases interchange.

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• Wetting floors in storage rooms.

• Adding crushed ice in shipping containers

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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 delayPost-harvest technology: to delayas long as possible, the tissue as long as possible, the tissue

disintegration/senescence phasedisintegration/senescence phase

Ripening Of Fleshy Fruits

• Last part of the fruit development process

FruitFreshWeight

Pollination/Fertilization

CellDivisionPeriod

Cell Expansion Period

Ripening PeriodRipening Period

Maturity (Full sized fruit)

Time

Ecological Function of Fruit Ripening

• Ripening must happen when the seeds are mature

• In order for ripening and seed maturity to happen together, the plant must control the process

So What Is Ripening?

• Increase in “sweetness” due to conversion of starch sugars

• Softening due to a breakdown of cell walls

• Less “tartness” due to decrease in acidity

• Increase in flavor compounds

• Color change

• Changes in respiration due to all

Starch to Sugar Conversion

Sugar

Starch

Days

%

Banana

Softening of Fruit

Days in storage

Soluble pectin

Firmness

Fru

it F

irm

nes

s, k

g p

ress

ure

% c

on

ten

t o

f so

lub

le p

ecti

n

Pectin Substances-Plant Gums

• Plant cell wall showing Pectin


• Role of Pectin in Plant Tissue (fruits)– In outer cell walls, closely associated with

cellulose – precursor of pectin: Protopectin– Absorb water and transfer it among cells– Responsible for firmness, texture (fruits &

veggies)– Softening during ripening– Breakdown of colloidal stability in fruit juices


• Change in pectin substances during ripening– Protopectin in middle lamella between cell

walls soluble pectin• Reduce cell wall thickness• Softening & Ripening

– Decrease the degree of esterification of carboxyl groups with methyl alcohol


Pectin is a polymer of α-Galacturonic acid with a variable number of methyl ester groups.

Methylated ester of Polygalacturonic acid

Chains of 300 to 1000 glalacturonic acid units

Joined with 1α→4 linkages

This structure shown here is three methyl ester forms (-COOCH3) for every two carboxyl groups (-COOH)

hence it is has a 60% degree of esterification, normally called a DE-60 pectin

What is Control Mechanism?

• That insures:

“ripening and seed maturity

happen together”

Controlling Ripening

• The mechanism plants use is a gas:

• Ethylene: C2H4 produced in response to seed maturation (less auxin???)

• How does ethylene control ripening?– Stimulates production of enzymes that

• Convert starch to sugar• Break down cell walls• Break down acids

Ripening Of Fleshy Fruits

IncreasingFruitFreshWeight,RespirationLevel,GasProductionEtc.

Pollination/Fertilization

CellDivisionPeriod

Cell Expansion Period Ripening Period

Ethylene

Flavorcomponents

Respiration

Optimum storage stageOptimum eating stage

STRAWBERRY –EXTERNAL COLOUR CHANGES. STRAWBERRY –EXTERNAL 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.

MANGO-INTERNAL COLOUR CHANGES

Presentation 3.2

Avoid the negative Avoid the negative effect of effect of external external

factorsfactors

To reduce and delay the action of the internal internal

factorsfactors that are responsible for product deterioration

Preservation Methods: Refrigeration/chilling : some fresh

produces can rapidly deteriorate under unrefrigeration, which affect the EP cost to be greater. Some precuts and convenience fresh produces such as salad greens should be delivered at temperature of approximately 34 ̊ F to 36 ̊F.

Presentation 3.2

Waxing: The wax prevents moisture loss and also contributes to the appearance of the produce. Some items likely to be waxed are apples, avocados, bell peppers, cantaloupes, cucumbers, eggplant, grapefruit, lemons, limes, melons, oranges, parsnips, passion fruit, tomatoes, and etc.

Controlled-atmosphere storage: This room is sealed and oxygen is removed, then variety of other gases are introduced in order to retarding spoilage and reducing the rate of respiration, but the produce that will rapidly deteriorate after removed from the controlled room.

Chemically treated produce: The produce will have a longer shell life.

What is chilling?

• A unit operation in which temperature of a food is reduced between -1 and 8 C.

Effect of temperature

• Biochemical changes caused by micro-organisms and naturally occurring enzymes increase with temperature.

Therefore, by reducing temperature we reduce the biochemical changes.

Why we chill foods?

• To reduce the rate of biochemical activity (respiratory rate of foods)

• To reduce the rate of microbial activity• To preserve sensory and nutritional value of

foods• Consumers consider chilled foods, because

easy to prepare, high quality, healthy natural and fresh

Enhances Shelf life

Presentation 3.2

Temperature control.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

Temperature (°C)

Assumed Q10*Relative

velocity of deterioration

Relative post-harvest life

Loss per day (%)

0 1 100 110 3 3 33 320 2.5 7.5 13 830 2 15 7 1440 1.5 22.5 4 25

Source: Kader & Rolle (2003)

Effect of temperature on deterioration rate of a non-chilling sensitive commodity

Presentation 3.2

Temperatures above or below theoptimal range, can cause productdeterioration due to:

• Chilling injury.• Freezing injury.• Heat injury.

Presentation 3.2

• Chilling Injury

• Chilling injury causes undesirable physiological changes (external or internal browning, skin blemishes, failure to ripen)

• Fruits and vegetables undergoing chilling injury should be stored above a certain temperature

• Chilling injury results from imbalance of metabolic activity

• There is an overproduction of some toxic metabolites

Examples of foods undergoing chilling injury

• Apples (<2-3 C)

• Bananas (< 12-13 C)

• Lemons (< 14 C)

• Mangoes (<10-13 C)

• Melons, pineapples, tomatoes

(< 7-10 C)

Presentation 3.2

Lowest safe temperature

(°C)Commodities

3 Asparagus, cranberry, jujube4 Cantaloupe, certain apple cultivars (such as McIntosh and Yellow Newton), certain avocado

cultivars (such as Booth and Lula), lychee, potato, tamarillo5 Cactus pear, cowpeas, durian, feijoa, guava, kumquat, lima bean, longan, mandarin,

orange, pepino7 Certain avocado cultivars (such as Fuerte and Hass), chayote, okra, olive, pepper,

pineapple, pomegranate, snap bean10 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 (mature-green), yam

Source: Kader & Rolle (2003)

Classification of chilling-sensitive fruits and vegetables according to their lowest safe temperature for transport and storage

Heat of respiration (Watts/tonne)

0 C 10 C 15.5 C

Apples 10-12 41-61 58-87

Bananas 73-82 65-116 -

Oranges 9-12 35-40 68

Carrots 46 93 -

Potatoes - 20-30 -

Source: Leniger and Beverloo (1975) and Lewis (1990)

Presentation 3.2

• Freezing produces an immediate collapse of tissues and total loss of cellular integrity.

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.

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Objective:Objective: to remove the field heat. to remove the field heat.

Movement of the caloric energy from the product to the cooling substance.

Air in the internal Cavity

Wax layer restricts the gases interchange.

Presentation 3.2

Modified and controlled atmosphere storage

21% Oxigene0.35% CO2

2% O21% CO2

Filters

Cold room0ºC

Apples, as any living entities..breath

Presentation 3.2

Range of storage duration (months)

Commodity

More than 12 Almond, Brazil nut, cashew, filbert, macadamia, pecan, pistachio, walnut, dried fruits and vegetables

6-12 Some cultivars of apples and European pears3-6 Cabbage, Chinese cabbage, kiwifruit, persimmon, pomegranate, some cultivars of Asian

pears1-3 Avocado, banana, cherry, grape (no SO2), mango, olive, onion (sweet cultivars), some

cultivars of nectarine, peach and plum, tomato (mature-green)<1 Asparagus, broccoli, cane berries, fig, lettuce, muskmelons, papaya, pineapple, strawberry,

sweet corn; fresh-cut fruits and vegetables; some cut flowers

Classification of horticultural crops according to their controlled atmosphere storage potential at optimum temperatures and relative humidifies

• 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

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 ATMOSPHERE MODIFIED ATMOSPHERE PACKAGING (MAP)PACKAGING (MAP)

Respirasi

C6H12O6 + O2 ------- CO2 +H20+ Energi (ATP) PANAS

O2

CO2

EnergyATP

H2O

DEFINITION• Modified atmosphere is a condition of atmosphere (normally in a package of

commodity) around the commodity that is different from that of air (78.08% N2, 20.95% O2, and 0.03% CO2).

• Usually this involves reduction of O2 and/or elevation of CO2 concentrations.• Modified atmosphere packaging (MAP) involves the exposure of produce to

the atmosphere generated in a package by the interaction of produce, the package and the external atmosphere.

• Different additives that may affect the atmosphere may be introduced into the package before it is sealed.

• The main feature distinguishing MAP from controlled atmosphere (CA) is that , in the case of MAP, active human involvement stops at the moment of sealing.

• Wide spectrum of techniques of MAP from Individual sealed packaging to the more intricate control of microorganisms in the new package of salad bar items.

• MAP is a multidisciplinary technology of maintaining freshness that utilises basic principles of chemistry, physics, plant physiology and pathology, microbiology, food science, engineering, polymer chemistry.

CO2i CO2e

O2i O2e

The MAP SystemPlastic FilmAreaVolumePermeability O2Permeability CO2thcikness

ProduceWeightOxygen uptakeCO2 Production

MAP should be considered as a supplement to proper temperature and relative humidity management

PRINCIPLES OF MAP

• MAP is a dynamic system during which respiration and permeation occur MAP is a dynamic system during which respiration and permeation occur simultaneously.simultaneously.

• Factor affecting both respiration and permeation must be considered when Factor affecting both respiration and permeation must be considered when designing a package.designing a package.

• Commodity mass, temperature, OCommodity mass, temperature, O22, CO, CO22, and C, and C22HH44 partial pressure and partial pressure and

stage of maturity are known to influence respiration in a package.stage of maturity are known to influence respiration in a package.

• Type, thickness, intended holes, and surface area of packaging film, as well Type, thickness, intended holes, and surface area of packaging film, as well as temperature, RH, and gradient of Oas temperature, RH, and gradient of O22 and CO and CO2 2 partial pressures across partial pressures across

the film, are known determinant of permeation.the film, are known determinant of permeation.

• Package equilibrium or steady state is defined as the point at which the Package equilibrium or steady state is defined as the point at which the commodity COcommodity CO22 production and O production and O22 consumption rates are equal to the consumption rates are equal to the

permeation rates of the respective gases through a package at a given permeation rates of the respective gases through a package at a given temperature.temperature.

• Poorly designed package will become anaerobic or develop unacceptable Poorly designed package will become anaerobic or develop unacceptable levels of COlevels of CO22 before equilibrium is achieved before equilibrium is achieved..

MAP for fruits and vegetables• Various films have been used

for packaging F&V to minimize respiratory anaerobiosis and potential microbiological hazards

• In China and Japan sealed-packaging has become a common new technique for citrus fruit storage.

• Sealed-package of many F&V are commonly available on the shelves of supermarket.

• One of the novel approaches in MAP of F&V is the introduction of a gas mixture of desirable composition into a package before sealing.

Presentation 3.2

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.

Food Preservation

• So, how does food preservation work?• All of the food preservation processes work by slowing down

the activity and growth of disease causing bacteria, or by killing the bacteria all together. They also slow down or stop the action of enzymes which can degrade the quality of the food.

– Temperature

– Water Activity

– pH

Food Preservation• Food preservation is the process of treating and handling food in such a way as to stop or greatly slow down

spoilage to prevent foodborne illness and extend its shelf-life.

• Food processing methods that are used to preserve foods include:

– Refrigeration and freezing

– Canning

– Irradiation

– Dehydration

– Freeze-drying

– Pickling

– Pasteurizing

– Fermentation

Cold storage

• Chilling – slowing microbical growth – reduce enzymatic and chemical reactions– slow postharvest metabolism– reduce moisture loss

• Freezing – slowing microbial and chemical reactions – water immobilization– reducing molecular mobility – some microbial destruction

Control of redox potential

• CA/MAP– prevent postharvest ripening– reduce microbial activity

Reducing aw

• drying

• freeze-drying

• humectants

• freezing– slowing microbial and chemical reactions– water immobilization– reducing molecular mobility

Fermentation

• inhibition of spoilage/pathogenic flora by beneficial microbial flora

• consumption of substrate for biochemical/chemical reactions

• production of antimicrobials

• acidification

Preservatives

• acidification – pH change– antimicrobial property

• other preservatives – antimicrobial– antioxidant– enzyme inhibitor– control redox potential

Chilling

• texture degradation in vegetables

• cold shortening of muscle foods, staling of bread

Freezing

• small many crystals desired, fast freezing entrapment of solutes, less than max concentration in the unfrozen phase

• large crystals, slow freezing max concentration of solutes, tissue damage, partial dehydration,

• local freeze concentration• freezer burn, sublimation of ice, dry brown spots on

poultry, beef• antimicrobial effect due to concentration, intracellular

freezing• destabilization of proteins, vitamin and pigment

degradation, oxidation of lipids

Concentration and dehydration

concentration > 20% moisture

dehydration < 20% moisture

evaporation, crystallization, sublimation, membrane separations

microorganisms survive, can recover, grow depending on aw

Modified atmosphere

• closed storage rooms, allow respiratory activity

• in packaging, remove air, replace with other gases, N2, CO2

• vacuum packaging

• vacuum, nitrogen: cheese, meat

• CO2 : fruits and vegetables, meat

Packaging

• glass, metal, plastics, paper• transport of gases, water vapor, low MW

components• resistance (mechanical, heat, chemical)• oxygen, carbon dioxide, moisture

permeability• light transmission• inertness

Aseptic packaging

1. product sterilization

2. package sterilization

3. Aseptic filling and sealing

Longer shelf life, better quality (?)

Hurdle technology

developed for limiting the growth of microorganisms in nonsterile foods (Leistner, 1978)

combined effects of preservation methods > sum of effects individually or large amounts of a single factor

Hurdle technology

has been used unintentionally

pickles pH + preservative (acid) + salt

sausage

aw + smoke + salt + spices + preservativesIMF (dried fruit, soft cookies)

aw + heating + preservatives pastırma

salt + spices + aw

•Thank you

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

• • inappropriate Infrastructure for produce inappropriate Infrastructure for produce packaging and storage.packaging and storage.• • improper transport conditions.improper transport conditions.• lack of planning (i.e.. harvesting). • lack of planning (i.e.. harvesting). • delays, improper conditions during • delays, improper conditions during distribution and marketing.distribution and marketing.

Primary damages are the result of inappropriate technologies and handling during the post-harvest chain:

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

Other Other treatmentstreatments

Pre-coolingPre-cooling

DryingDrying

Selection,Selection,cleaning cleaning

and and disinfectiondisinfection

ReceptionReception

Grading Grading

Packing and Packing and packagingpackaging

StorageStorage TransportTransport

HarvestingHarvesting

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).

HarvestinHarvestingg Associated hazardsAssociated hazards

Presentation 3.2

RecommendatioRecommendationsns

• 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

• 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 Produce receptionreception

Associated hazardsAssociated hazards

Presentation 3.2

Presentation 3.2

Possible Hazards associated

Pre-coolingPre-cooling

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

Definir actores/roles/Expectativas.Cleaning and Cleaning and

disinfectiondisinfection

Definir actores/roles/Expectativas.Washing methods:

Web methods:• Immersion (product floating).• Spraying .

Dried methods:• Brushing.• Inhalation/aspirate.

Objective: Removing impurities from the product.

Presentation 3.2

Definir actores/roles/Expectativas.Cleaning and Cleaning and

disinfectiondisinfection

Definir actores/roles/Expectativas.• product water sensitivity.

• poor water quality.• mechanical damage (inappropriate conditions of brushes, etc).• water accumulation in the product can cause product quality decay.

Possible Hazards associated

Presentation 3.2

Associated Hazards

GradingGrading

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 Packing and packagingpackaging

Definir actores/roles/Expectativas.

• 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).

Associated Hazards

Presentation 3.2


• 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.

Packing and Packing and packagingpackaging Associated Hazards

Presentation 3.2

Storage 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.

Presentation 3.2

TransportTransportAssociated 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

Other Post-Other Post-harvest harvest

treatmentstreatments


Associated hazards: increase product’s susceptibility to

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

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.

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.

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.

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 food deterioration and its causes

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