Best Practices in Postharvest Management of Leafy Vegetables in Greater Mekong Subregion docx

Proceedings
Antonio L. Acedo Jr.
Katinka Weinberger
Editors
25-27 October 2007
Hanoi, Vietnam
Best Practices in
Postharvest
Management
of Leafy
Vegetables in
Greater Mekong
Subregion
Countries








Best Practices in Postharvest
Management of Leafy Vegetables
in Greater Mekong Subregion
Countries

AVRDC - The World Vegetable Center
Shanhua, Taiwan







Best Practices in Postharvest
Management of Leafy Vegetables in
Greater Mekong Subregion Countries



Proceedings of a GMS workshop
25-27 October 2007
Hanoi, Vietnam

Antonio L. Acedo Jr.
Katinka Weinberger

Editors









AVRDC - The World Vegetable Center
AVRDC - The World Vegetable Center is the leading international nonprofit
organization committed to alleviating poverty and malnutrition in the
developing world through the increased production and consumption of safe
vegetables.

AVRDC - The World Vegetable Center
P.O. Box 42
Shanhua, Tainan 74199
TAIWAN

Tel: +886 6 583 7801
Fax: +886 6 583 0009

Email:
Web: www.avrdc.org

AVRDC Publication No: 09-731
ISBN 92-9058-178-6

Editor: Maureen Mecozzi
AVRDC Publication Team: Kathy Chen, Vanna Liu, Chen Ming-che, Shiu-luan Lu

© 2009 AVRDC - The World Vegetable Center

Citation
Acedo AL Jr., Weinberger K, editors. 2009. Best practices in postharvest management
of leafy vegetables in Greater Mekong Subregion countries: Proceedings of a GMS
workshop, 25-27 October 2007, Hanoi, Vietnam. AVRDC Publication No. 09-731.
AVRDC - The World Vegetable Center, Taiwan. 165 p.
Organizers
AVRDC - The World Vegetable Center, ADB Postharvest Project Office
Vientiane, Laos

Research Instituted of Fruits and Vegetables
Hanoi, Vietnam


Funding
Asian Development Bank, through RETA 6376


Workshop participants

Front (L-R): Ms. Nguyen Thi Hanh, Vietnam; Ms. Nguyen Thi Thuy Linh, Vietnam; Ms.
Win Win Kyi, Myanmar/ AVRDC-WVC Small Enterprise Advisor, Dr. Sasitorn
Tongchitpakdee, Thailand (Processing Expert); Dr. Chu Doan Thanh, Vietnam; Dr.
Antonio Acedo Jr., Philippines/AVRDC-WVC Regional Project Coordinator, Dr. Chen
ZongQi, China, Dr. Lemuel Diamante, Philippines (Processing Expert)
Back (L-R): Mr. Borarin Buntong, Cambodia; Mr. Nguyen Dinh Hung, Vietnam; Dr.
Varit Srilaong, Thailand; Dr. Kyaw Nyein Aye, Myanmar; Ms. Luong Thi Song Van,

Vietnam; Dr. Sirichai Kanlayanarat, Thailand; Dr. Li Hong, China; Dr. Li YunShou,
China; Mr. Thongsavath Chanthasombath, Lao PDR; Mr. Chansomone Phomachan,
Lao PDR; Mr. Nguyen Khac Trung, Vietnam; Mr. Nguyen Duc Hanh, Vietnam







Contents

Acknowledgements

iii
Foreword

iv
Part 1: Problems and Needs of Leafy Vegetable Value
Chains in Poverty-stricken Upland Areas in CLV and
Available Country Interventions

1
Problems and Needs of Leafy Vegetable Value
Chains in Selected Upland Areas in Cambodia
and Available Country Interventions
Mr. Borarin Buntong

2
Problems and Needs of Leafy Vegetable Value

Chains in Selected Upland Areas in Lao PDR and
Available Country Interventions
Mr. Thongsavath Chanthsombath

9
Problems and Needs of Leafy Vegetable Value
Chains in Selected Upland Areas in Vietnam and
Available Country Interventions
Dr. Chu Doan Thanh

17
Workshop Summary

25
Part 2: Postharvest Technologies for Fresh Leafy
Vegetables

27
Postharvest Technologies for Fresh Leafy
Vegetables in Myanmar
Dr.Kyaw Nyein Aye

28
Postharvest Technologies for Fresh Leafy
Vegetables in Yunnan, China
Dr.Chen ZongQi

37
Postharvest Technologies for Fresh Leafy Vegetables in
Thailand

Dr.Sirichai Kanlayanarat

44
Postharvest Technologies for Fresh Leafy
Vegetables
Dr.Antonio Acedo Jr.
53

Workshop Summary

83
Part 3: Processing Technologies for Fresh Leafy
Vegetables

84
Processing Technologies for Leafy Vegetables in
Myanmar
Ms. Win Win Kyi

85
Processing technologies for Leafy Vegetables in
Yunnan, China
Dr.Li Hong

92
Processing Technologies for Leafy Vegetables in
Thailand
Dr.Varit Srilaong

104

Processing Technologies for Leafy Vegetables in
the Philippines and Other Parts of the World
Dr.Lemuel Diamante

114
Processing Technologies for Leafy Vegetables
Outside GMS
Dr.Sasitorn Tongchitpakdee

133
Workshop Summary

144
Part 4: Concluding Discussion

146
Upland Agriculture Development in Yunnan, China
Dr. Li YunShou

147
Summary of General Discussion

151
Annex

152
Program

153
Participants

159




Acknowledgements


AVRDC - The World Vegetable Center and workshop participants gratefully
acknowledge financial support from the Asian Development Bank through
the RETA 6376 project. The organizers also thank the people who assisted in
the preparations for the workshop and who facilitated and accommodated the
group during the study tour.

iii
Foreword


Postharvest technology (PHT) is crucial for perishable commodities such as
leafy vegetables to bring down losses, improve marketing, and increase farm
returns. It is of particular importance in the Greater Mekong Subregion
(GMS), one of the world’s leading vegetable producers and consumers, where
the vegetable industry is seriously constrained by high postharvest losses and
poor marketing systems. Initiatives to promote the postharvest sector could
fuel economic growth, promote rural sustainability, and ease the problems of
poverty, unemployment, and malnutrition in developing countries. PHT
enables countries to participate effectively in domestic and international trade
in light of increased competition due to trade liberalization and market
reforms.

AVRDC - The World Vegetable Center designed and instituted two PHT
initiatives for vegetables in GMS funded by the Asian Development Bank
(ADB). The new ADB RETA 6376 project pursues PHT development for
leafy vegetables, targeting small farmers and processors in upland areas in
Cambodia, Lao PDR, and Vietnam. This project complements the ongoing
initiative on fruit and vegetables (ADB RETA 6208).

The ADB RETA 6376 workshop on Best Practices in Postharvest
Management of Leafy Vegetables in GMS Countries held in Hanoi, Vietnam
on 25-27 October 2007 sought to build the groundwork for future PHT
research and development work for leafy vegetables in the region. The

specific objectives of the workshop were to:

 examine the needs and problems of leafy vegetable farmers and other
supply chain actors in upland areas of Cambodia, Laos, and Vietnam,
and the existing country initiatives addressing those needs/problems
 review and document the fresh produce handling and processing
technologies for leafy vegetables available in GMS and elsewhere
 identify PHT to be developed and formulate the R&D details
 foster regional cooperation to advance the vegetable industry in GMS
countries

The workshop gathered PHT experts, key project players and other
development workers in GMS to discuss and analyze the initial findings of
surveys on leafy vegetable value chains in upland areas of Cambodia, Laos,
and Vietnam. Existing country interventions were examined in Session 1, and
iv
experiences shared in postharvest handling (Session 2) and processing
(Session 3) of leafy vegetables, including indigenous techniques and those in
commercial practice with particular emphasis on simple, low-cost
innovations. Session 1 concluded with a list of priority problems/needs;
Sessions 2 and 3 with postharvest handling and processing technologies to be
developed by the Cambodia, Laos, and Vietnam teams, respectively. Paper
presentations preceded each workshop session.

Best Practices in Postharvest Management of Leafy Vegetables in GMS
Countries contains the papers presented in each session and the summary of
the following workshop discussion. It has four parts: The first three parts
correspond to the three workshop sessions, and the last part covers the
concluding discussion, including a presentation about China’s experience in
developing upland agriculture. This proceeding can serve as a reference for

development workers, policy makers and other stakeholders in developing
countries aiming to strengthen the vegetable industry through improving
value-addition activities after harvest.



Dr. Antonio Acedo, Jr.
Dr. Katinka Weinberger
AVRDC - The World Vegetable Center
v
PART I: Problems and needs of leafy
vegetable value chains in poverty-stricken
upland areas in Cambodia, Laos, and
Vietnam, and available country
interventions

Problems and Needs of Leafy Vegetable
Value Chains in Selected Upland Areas in
Cambodia and Available Country
Interventions

Borarin Buntong
Postharvest Technology Laboratory Supervisor/Lecturer
and RETA 6376-Cambodia Team Expert Member
Faculty of Agro-Industry, Royal University of Agriculture
Phnom Penh, Cambodia

Mong Vanndy
National Coordinator, RETA 6376/ 6208 Project
Deputy Director, Kbal Koh Vegetable Research Station
Department of Agronomy and Agricultural Land Improvement
Phnom Penh, Cambodia


Introduction

Cambodia is one of the least developed countries in the Greater Mekong
Subregion. It is located between latitude 10-15
o
N and longitude 102-108
o
E. It

has 24 provinces, three cities, and a total land area of 181,035 km
2
. The
upland areas are located on the eastern side of the Mekong River.

Vegetables rank second to rice among cultivated crops. Total production area
is about 70,000 hectares with annual yield of 460,000 tons (FAO, 1999).
Vegetables, particularly the leafy type, serve as a major source of income of
many farmers and are the main and cheap source of nutrition for low-income
families, especially those living in upland areas.

Through the ADB-funded RETA 6376 spearheaded by AVRDC - The World
Vegetable Center, development initiatives to introduce postharvest
technology (PHT) and expand market opportunities for leafy vegetables were
made possible, targeting small farmers and processors in upland areas in
Cambodia, Lao PDR, and Vietnam. A major initiative is the leafy vegetable
value chain survey to gather benchmark information on present postharvest
practices, problems, and needs of farmers and processors to be used as a basis
for subsequent R&D and training programs of the project. This paper presents
some of the initial findings of the survey in Cambodia.

2 Workshop Proceedings, 25-27 October 2007
Vegetable Value Chain Survey

Priority leafy vegetables and survey sites


Survey site and crop priorities of Cambodia, Lao PDR, and Vietnam partners
were set during the RETA 6376 Inception Workshop held on July 3-5, 2007
in Vientiane, Lao PDR. For Cambodia, Kampong Cham and Siem Reap

provinces were identified as the two upland survey areas; common cabbage
and Chinese kale were selected as priority leafy vegetables (Fig. 1).

Preparatory activities


Initial arrangement. The RETA 6376-Cambodia team led by the National
Coordinator conducted an exploratory trip to the two provinces in September
2007 to identify specific areas in each province to be covered, make
administrative arrangements with local authorities, and identify possible
survey respondents.

Figure 1. The two sites (Siem Reap and
Kampong Cham) and priority leafy vegetables of
the Cambodia surveys.





Best Practices in Postharvest Management of Leafy Vegetables in GMS Countries 3


Figure 2. Some postharvest practices for fresh leafy vegetables in
Cambodia. Top, l-r: field handling of harvested produce; sorting,
trimming, cleaning; air drying Chinese kale leaves after washing.
Bottom, l-r: packaging; transport.

Survey questionnaire translation. Two questionnaires, one for farmers and the
other for processors, sent by AVRDC headquarters (HQ) were translated into

Khmer prior to the enumerators’ training.

Enumerators’ training. The training for survey enumerators was conducted
by the survey expert from AVRDC HQ in the Training Room of Kbal Koh
Vegetable Research Station (KKVRS) on 24-28 September 2007. There were
11 participants from KKVRS and Department of Agriculture. During the
training, the Khmer translation of the farmer and processor questionnaires
was checked, revised, pretested, and finalized.

Conduct of survey


The survey in Kampong Cham was conducted on 1-5 October 2007 and the
survey in Siem Reap was conducted on 6-9 October 2007. As planned, 100
respondents were covered in each province, for a total of 200 respondents.
However, the target number of processors was not met, similar to the Lao and
Vietnam surveys. Overall, only four processors of common cabbage (no
processor of Chinese kale), all from Kampong Cham, were interviewed; the
rest were farmers.


4 Workshop Proceedings, 25-27 October 2007
Initial findings

The RETA 6376-Cambodia team expert member from the Royal University
of Agriculture who handled data input was trained by the AVRDC-HQ survey
expert in survey data encoding. The following are some initial findings of the
survey:

Harvesting and field handling. Harvesting of cabbage and Chinese kale is

done manually (Fig. 2a). The time of harvesting depends mainly on the order
from the collector. The harvested produce may be left in the field to dry
(cabbage) or brought to a packing area near the field. Sometimes, packing is
done in the field. Some of the problems identified are as follows:

 improper maturity
 loose handling (no container)
 careless handling resulting in leaf crushing and/or head bursting
 exposure to the sun

Packinghouse operations, packaging, and transport. At the packing area, the
produce is trimmed, cleaned, and sorted (Fig. 2b-c). Some outer leaves of
common cabbage are removed, while for Chinese kale, some farmers separate
the leaves individually. Cabbage usually is not washed; Chinese kale is
washed and air-dried. There is no quality standard used during sorting.
Collectors dictate quality criteria for acceptance. The produce is transported
unpacked, or packed in bamboo basket of different shapes and sizes (Figure
2d-e), plastic bags, or sacks. Transport is done by small truck (Fig. 2f) or
motorcycle with or without trailer. Some problems observed:

 large containers that could result in high compression damage and
increase the tendency of handlers to drop the container due to its
heavy weight
 overpacking of containers
 mixing of many types of containers of produce in the transport load
without proper arrangement (improper stacking)
 overloading of transport load
 inability of plastic bag to protect the produce
 loose transport (produce transported without container)
 exposure to sun and rain during transport

 delays during transport or distribution

Best Practices in Postharvest Management of Leafy Vegetables in GMS Countries 5
Storage. Farmers do not have storage facilities. The produce is kept in a
shaded area of the house or collected immediately by collectors and
wholesalers. Losses of produce during handling and transport to market are
usually passed on by collectors and wholesalers to the farmers by requiring
them to provide a weight allowance such as 1-3 kg additional weight per unit
order.

Processing. Chinese kale is usually marketed and consumed fresh. Cabbage is
consumed fresh and also is processed, mainly pickled (Fig. 3). The usual
procedure includes removal of outer leaves, slicing the cabbage head into
quarters, salting, and fermentation for 1-2 days. Aside from food safety
concerns, some problems noted by processors include:

 short shelf life of 1-3 days
 fast color deterioration
 no uniform quality
 lack of skill and knowledge in processing
 no enough capital and lack of labor

General problems/needs. The survey found that farmers and processors need
training in PHT to improve their knowledge and skills to operate a profitable
enterprise, and require assistance in sourcing capital.
Available Interventions Addressing Postharvest Problems

Some farmers use their own creativity to reduce losses of cabbage and
Chinese kale as shown in Figure 4. Observed traditional innovations include:

 use of fresh banana leaves to line of bamboo basket to protect the
produce from the sharp edges of the container
 proper arrangement of Chinese kale leaves inside the container to
minimize leaf tearing and crushing
 individual wrapping of cabbage heads with old newsprint
 use of plastic bags to minimize weight loss, which is a form of
modified atmosphere packaging
 exposing the cut butt end of cabbage heads to the heat of the sun for
1-2 hours before collection, to allow the cut end to dry and minimize
bacterial soft rot
 washing Chinese kale to allow rehydration aside from cleaning the
produce
6 Workshop Proceedings, 25-27 October 2007
The fermentation process to produce pickled cabbage is a traditional
technique, although it needs improvement to address the problems
encountered.

There is no PHT development for leafy vegetables in research and academic
institutions. Aside from the scarcity of trained personnel in PHT, there is a
lack of funding support for leafy vegetable PHT research and development.



Figure 3. Fermented common cabbage in retail
market display in Cambodia.


Figure 4. Some indigenous/present postharvest techniques
for leafy vegetables.
Best Practices in Postharvest Management of Leafy Vegetables in GMS Countries 7

Conclusion

The survey opens up opportunities for proper application of development
initiatives. The problems and needs identified are give only a partial picture
of the situation, but do indicate that the actions needed are consistent with the
objectives of development projects such as RETA 6376.

8 Workshop Proceedings, 25-27 October 2007
Problems and Needs of Leafy Vegetable
Value Chains in Selected Upland Areas in
Lao PDR and Available Country
Interventions

Thongsavath Chanthasombath
National Coordinator, RETA 6376/6208 Project
Deputy Director, Crop Multiplication Center, Department of Agriculture
Vientiane, Lao PDR


Introduction

The Lao PDR economy is agriculture-based, similar to other Greater Mekong
Subregion (GMS) countries. With a land area of 236,800 km
2
and a
population of more than 6 million, Lao PDR is located at the heart of GMS,
bordering with Cambodia, China, Myanmar, Thailand, and Vietnam (Fig. 1).
The country could play a strategic role in intraregional trade of agricultural
produce. In line with the government’s policy and the Ministry of Agriculture
and Forestry’s strategy to modernize agriculture and promote exports,

together with market-oriented economic liberalization, dramatic
improvements in agriculture were achieved. Collaboration with development
agencies that share common goals and objectives is being pursued, including
the AVRDC-initiated and ADB-funded PHT programs for vegetables (RETA
6376 and RETA 6208).

Vegetables are the second most important agricultural crops after rice. Total
cultivated area is 85,710 hectares, producing 744,450 tons of produce (DOA,
2005). Leafy vegetables account for about 50% of the total vegetable
production, with area and volume of production of 45,240 hectares and
356,610 tonnes, respectively. Vientiane Province is the major upland growing
area, located north of the capital, Vientiane; Champasak is the leading
vegetable-producing province at the southern tip of the country on the border
with Cambodia and Thailand.

PHT development for leafy vegetables was launched through RETA 6376.
One major activity is the value chain survey targeting small farmers and
processors in selected upland areas. This paper presents some of the initial
findings of the survey in Lao PDR.

Best Practices in Postharvest Management of Leafy Vegetables in GMS Countries 9
Vegetable Value Chain Survey

Priority leafy vegetables and survey sites


During the RETA 6376 Inception Workshop on July 3-5, 2007 in Vientiane,
common cabbage and Chinese/green mustard were identified as the priority
crops, while Vang vieng and Hinheub (in place of Kasy) Districts of
Vientiane Province were selected as the survey sites. After further

consultation with the provincial agriculture agency, Kasy District was
reinstated as a survey site as originally proposed (Fig. 1).

Preparatory activities


Initial arrangement. The National Coordinator, Director-General of the
Department of Agriculture, and the RETA 6376/6208 Regional Project
Coordinator held a meeting with officials of the provincial agriculture agency
at the provincial capital, Phonhong. The team received assurances of support
for the project and assistance in other requirements of the survey, such as
identification of respondents. District agriculture staff (DAS) were selected to
be survey enumerators. The DAS attended enumerators’ training a week later.


Figure 1. The two sites (Vang vieng and Kasy districts)
of the Lao PDR surveys.

10 Workshop Proceedings, 25-27 October 2007

Figure 2. Some postharvest practices for fresh leafy vegetables in Lao
PDR. Top, l-r: Loose hauling and packing in bamboo basket. Trimming
of outer leaves and packing in plastic bag. 68-kg capacity bamboo
basket. Bottom, l-r: Baskets of cabbages awaiting transport. Truckload
of cabbages transported bare.

Survey questionnaire translation. Two questionnaires, one for farmers and the
other for processors, sent by AVRDC headquarters (HQ) were translated into
Lao prior to the enumerators’ training.

Enumerators’ training. The training for survey enumerators was conducted
by the AVRDC HQ survey expert in the Training Room of the Crop
Multiplication Center (CMC) on 4-7 September 2007. There were 10
participants, 6 DAS and 4 CMC staff including the National Coordinator. The
AVRDC-ADB Regional Project Coordinator and Small-scale Enterprise
Advisor also attended some parts of the training. During the training, the Lao
translation of the farmer and processor questionnaires was checked, revised,
pretested, and finalized.

Conduct of survey


The survey in Kasy District was conducted on 10-14 September 2007 and in
Vang vieng from 17-21 September 2007, with 100 respondents from each
district, for a total of 200 respondents. Due to a limited number of processors,
only 18 processors of both cabbage and mustards were surveyed, eight from
Best Practices in Postharvest Management of Leafy Vegetables in GMS Countries 11
Kasy and 10 from Vang vieng. Selected project staff members were trained
by the AVRDC-HQ survey expert to use software for encoding survey data.

Initial findings


Farmers. Figure 2 shows some of the postharvest handling practices for
cabbage. Cabbages are loosely handled (without packaging containers),
packed in big bamboo baskets (usually 68 kg capacity), or trimmed of outer
leaves (wrapper leaves) before packing in plastic bags. The major problems
and needs of cabbage farmers obtained during the survey are:

 Overproduction: Cabbage usually is grown after rice during the dry

and cool period of the year, from December to March. When harvest
time comes, there is an oversupply of produce and price of cabbage
drops drastically.
 Overmaturity: This is manifested as cracking and internal browning
of the cabbage head. This is a frequent occurrence, as most farmers
wait for the order from collectors and wholesalers rather than harvest
the crop with no sure market.
 Allowance for postharvest loss: Collectors/wholesalers usually
require 25% allowance for losses incurred when handling the produce
from the farm to the market. Because they usually provide big plastic
bags as packing material with 12-kg capacity, farmers fill each plastic
bag with 15 kg cabbage. Otherwise, collectors/wholesalers will not
buy the farmers’ produce.
 Losses due to the use of plastic bags: Use of plastic bags as packing
material is beneficial in preventing too much water loss (weight loss).
Cabbages are harvested in the morning (0800-1000), packed in plastic
bags, piled along the road and sometimes covered by leaves, and
picked up by the collectors in the afternoon (1400). Sweating inside
the bag is common, a condition that favors rotting during subsequent
handling. Plastic bags cannot protect the produce from handling
hazards resulting from mechanical damage. High losses due to
trimming of damaged leaves and rotten parts (due to bacterial soft
rot) of the cabbage head are incurred (Fig. 3).
 Need for storage facility: Farmers acknowledged that if they could
store their cabbages for at least one month, they could have better
control in harvesting and marketing their produce. This is because
after one month, the price of cabbage normally increases.
 Other forms of loss incurred: Drying of outer leaves, insect-damaged
heads
12 Workshop Proceedings, 25-27 October 2007

Figure 3. Trimming losses in cabbage due to physical injury and rotting
and leafy wilting and yellowing in Chinese mustard.




Figure 4. Lao technique in Chinese mustard fermentation.

Best Practices in Postharvest Management of Leafy Vegetables in GMS Countries 13
For Chinese/green mustard farmers, the major problems that contribute to
postharvest loss are:

 Wilting, weight loss and yellowing of leaves (Fig. 3)
 Insect damage
 No uniform size (small)
 Overmaturity: This is manifested by the production of flower stalks,
because some farmers have to delay harvest to wait for orders from
collectors and wholesalers.
 Allowance for postharvest loss: For green mustard, farmers are
required to provide1 kg allowance for loss per 12 kg plastic bag of
produce. For Chinese mustard, this is not required.
 No storage facility: Farmers preferred to wait for orders from
collectors and wholesalers rather than harvest the crop at the right
maturity. The practice of soaking stems in water can keep mustards
for only one day; then, wilting and yellowing rapidly develop.
Farmers need to extend storage life of mustards.
 Limited processing techniques

Processors. Figure 4 illustrates the Lao technique in fermented mustard

processing, similar to that practiced for common cabbage. Sorting is first
done followed by separating individual leaves, washing, adding and mixing
with salt, and fermenting in a pot for 1-2 days. Prior to fermentation, the
vegetable is mixed again with salt, monosodium glutamate, and rice water.
The major problems and needs of processors are:

 Short shelf life: Fermented mustard or cabbage usually lasts for only
1-3 days, depending on the salt concentration used.
 Rapid quality loss: The fermented vegetable rapidly deteriorates in
aroma (foul odor development), color (from green to brown-yellow)
and taste (very sour). If consumed, diarrhea usually results.
 Improvement of technique
Available Interventions Addressing Postharvest Problems

Figure 5 shows some of the indigenous/traditional techniques of leafy
vegetable farmers and processors observed during the survey.

 Use of plastic bag for packaging, a form of MAP technique
 Cooling by top icing or ice packing
14 Workshop Proceedings, 25-27 October 2007