1. Introduction
‘Nam Dok Mai’ mango (
Mangifera indica Linn) is one of Thailand’s most economically important fruits due to its flavor and bright yellow flesh, which is favored by consumers in both domestic and export markets. The major production areas of ‘Nam Dok Mai’ mango are located in the Chiang Mai province in the north, the Phitsanulok province in central Thailand, the Loei and Nakhon Ratchasima provinces in the northeast, and the Prachuap Khiri Khan province in the south [
1]. The on-season production of mango in Thailand occurs from April to May and it extends to late July in some regions. Early off-season production occurs from January to March and late off-season production occurs from August to December [
2]. The export volume of fresh mangoes in 2017 was 55,792 tons, which was valued at 70 million USD, with Nam Dok Mai being the main cultivar [
1]. Thailand exports mangoes mainly to Japan, Korea, Vietnam, China, and Malaysia [
2]. ‘Nam Dok Mai’ mango is a preferred product in many countries due to favorable characteristics such as attractive skin color, pulp color, taste, and flavor.
However, a crucial problem in terms of ‘Nam Dok Mai’ mango production for export is the post-harvest disease infection of anthracnose and stem end rot diseases caused by
Colletotrichum gloeosporioides and
Lasiodiplodia theobromae, respectively.
C. gloeosporioides is the most significant fungus that can infect all parts of a mango tree including the stem, leaf, flower, immature fruit, and mature fruit [
3]. Consequently, anthracnose as a latent infection may enter the mango during the immature stage or even during flowering [
4,
5]. The symptoms of the disease do not express themselves in an infected unripe mango but appear when the mango ripens. The symptoms were seen to be black spots or flecks on the skin of ripe mangoes. In recent years, researchers have examined the control of the anthracnose disease during preharvest and post-harvest processes such as chemical use [
6], biocontrol [
7], cultivation [
8], and so on.
In practice, mango production processes both at the preharvest (at the field of production) and post-harvest (at the packing house) stages had different regulations and protocols for certification. These led us to investigate the problem through the material and information flows obtained from the mango production process, ranging from up-stream to down-stream processes, and to look for risk points for post-harvest disease control. The examination of materials and information flows during production processes could be a powerful tool to determine the traceability of ‘Nam Dok Mai’ mango production system. Our study focused on mangoes exported to Japan in particular. The fruit had to be produced under specific conditions approved by Good Agricultural Practices (GAP) in the field, and as per a special requirement, they had to be treated using vapor heat treatment (VHT) to increase the pulp temperature to 47 °C constant for 20 min during post-harvest handling [
9]. Furthermore, the maximum residue limits (MRL) of Chlorpyrifos, an important pesticide, on the fruit had to be less than 0.05 mg·L
−1 [
10].
Supply chain management (SCM) is a processing alignment of material, financial, and information flows to improve activities and processes. SCM involves the management of relationships between efficient production and the supply of products from farms to customers [
11]. To evaluate SCM, the supply chain operation reference (SCOR) model, which provides a framework of business processes, practices, and technology design [
12,
13], has been used as a strategic tool. This study focused on mapping the material flow and information flow of mangoes exported to Japan. The SCOR model of the mango supply chain was monitored. Diseases infecting mangoes during post-harvest were monitored and the risk points of diseases infecting mangoes during the mango supply chain were critically analyzed. This study resulted in certain critical findings regarding the risks of disease infection during mango processing and mango export both at the preharvest and post-harvest stages.
2. Materials and Methods
The material and information flows in the supply chain of ‘Nam Dok Mai’ mango for export to Japan were collected from mango growers and an export company in 2016–2017. The data of post-harvest disease infection during the supply chain of ‘Nam Dok Mai’ mango was identified using observation, questionnaires, and interviews with growers and exporter staff. This study adapted the method from Olsen and Aschan (2010) [
14] and the processed mapping of mango exported to Japan is shown in
Figure 1.
2.1. Choices of Pilot Company (Stage 1)
A pilot company located at the Rojana Industrial Park in the Ayutthaya province, Central Thailand (an hour from the center of Bangkok), which exports ‘Nam Dok Mai’ mango to Japan, was selected and 44 growers who supply mangoes to the company from different production locations across the country were chosen.
2.2. Outlining Observation (Stage 2)
The exporter was interviewed to gain information regarding the material flow procedure of post-harvest mango handling. The problems of barriers during management were also recorded.
2.3. Choices of Informants and Formulating Questions (Stage 3)
The primary problem identified by the mango exporter was post-harvest disease. Therefore, the questionnaire was based on preharvest and post-harvest mango management following mango cultivation processes and the Thailand GAP guide.
2.4. Interviews and Document Analysis (Stage 4)
2.4.1. Mango Growers
Mango growers who supply ‘Nam Dok Mai’ mango to the company were chosen from 4 different locations and the list included 12 growers from the Phetchabun province (north), 11 growers from the Nakhon Ratchasima province (northeast), 11 growers from the Sa Kaeo province (east), and 10 growers from the Prachuap Khiri Khan province (south). All growers were classified into 3 groups based on farm sizes: small (< 6.4 ha), medium (6.4–16 ha), and large farms (> 16 ha). The information was collected from growers through interviews and relevant documents were collected. The questionnaires referred to the topic of “how to produce mangoes of sufficient quality for supply to the exporter”.
2.4.2. Exporter
The second set of observations were made at a packing house belonging to the mango exporter. An observation form was used to evaluate the handling process. The information was analyzed to gauge the importance of processing in preventing post-harvest diseases.
2.5. Collection of Mangoes for Disease Evaluation (Stage 5)
At the field of production, ‘Nam Dok Mai No. 4’ and ‘Nam Dok Mai Sithong’ mangoes were sampled from 5 orchards in the Phetchabun province (30 fruits from each). The fruit was washed, dipped in 400 mg·L−1 ethephon, and then incubated at ambient conditions (25 °C, 60–70% RH).
At the packing house, the mangoes were sampled at each step (32 fruits per step) of the mango processing line. The fruit sampled during Step 1 (material receiving), Step 2 (pedicle cutting and washing), and Step 3 (hot water dipping) was dipped in 400 mg·L−1 ethephon. All sampled fruit was then kept at 25 °C, 60–70% RH for 9 days to allow for ripening and the development of disease symptoms was then checked. The infected fruit was counted when the fruit showed sharp spots of disease.
Percentage of disease incidence in mangoes was calculated using the following formula:
When
2.6. Analysis of Data (Stage 6)
The collected data was analyzed using a SPSS program (Version 19., IBM Corporation, Armonk, NY, USA) on MS Windows and reported as frequencies and averages. The item findings were analyzed using the SCOR model and the critical control points of post-harvest disease infection during the supply chain of ‘Nam Dok Mai’ mango was identified by mapping between the material and information flows.
4. Conclusions
There are 4 critical points affecting post-harvest disease infection which have been obtained from the study of the SCM of mango production for export to Japan, and this study examined processes ranging from pre- to post-harvest handling. In the production field, the selection of the cultivar ‘Nam Dok Mai’ mango was the first attempt to reduce post-harvest loss by disease infection since ‘Nam Dok Mai Sithong’ mango is more tolerant to anthracnose. Second, the removal of pruned branches and rotten fruit from the production area could also dramatically reduce an accumulation of diseases. Third, fruit bagging not only improves the quality of fruit but also reduces the cost of chemicals used and disease incidence. Furthermore, on the part of the exporter, the rate limiting step for a significant decrease in post-harvest disease expression is hot water treatment at 50 °C for 3 min prior to the ethephon treatment of ripening induction.