Exploration of the effects of postharvest handling of fruits and vegetables along fresh produce chains using logistics and computer modelling: A case study in Zimbabwe: A thesis submitted in partial fulfilment of the requirements for the degree of Master of Science at Lincoln University

Abstract

Agriculture is not only a significant export earner for many economies but is the largest employer globally. Horticultural produce such as fresh fruit and vegetables are key commodities on local and international trade markets. However, approximately 3 billion tonnes of food that is intended for human consumption is lost or wasted along the agri-fresh supply chains. These losses imply a decline in revenue and deprivation of income for some households. Identification of the sources and causes of these losses is an essential postharvest management strategy that is key in enhancing food and nutrition security and livelihood sustainability in developing countries. The goal of the study was to characterise postharvest losses in banana, orange, pea and tomato supply chains in Zimbabwe. The study also identified possible mitigation strategies for the losses within the context of operation they were occurring. Three approaches were made use of in the study. Firstly, a literature review of similar studies carried out in other countries aided in the development of questions for a semi-structured interview-based questionnaire. The instrument was used to map the supply chains from the producer (farmer) to the retail store or the point from which customers purchased their produce. Results showed that the key chain participants were producers, traders, retailers, marketers, exporters and wholesalers. Producers or farmers were further subdivided into large-scale commercial, small-scale commercial and small-scale subsistence farmers. Large-scale commercial farmers exported most of their produce whilst small-scale commercial and small-scale subsistence farmers mostly supplied the domestic market. Secondly, observations were made following interviews. These aided in corroborating the information gathered from the interviews with the activities that were taking place at different points of the supply chain. Unsanitary activities were observed at the small-scale subsistence farmers level and at the traders’ market stalls. Thirdly, simulation models were developed for the orange supply chain, using information gathered from the interviews and the observations. In conclusion, the results obtained in the study indicated that there is need for enhancement of agricultural training and extension services to educate traders and the small-scale subsistence farmers on proper postharvest handling of produce. They form the largest group of farmers in Zimbabwe, with the least farming space and limited knowledge on postharvest handling. Quality of road and public farmers markets infrastructure requires for the intervention of relevant ministerial and national governing bodies. On matters relating to public health, there is need to educate the public on the dangers of using chemicals not meant for fresh-produce in dealing with nuisance pests and insects. The simulation study highlighted the need for all players in the agri-fresh supply chain to record and keep data on movement of produce. This information should incorporate volumes traded and lost, waiting times, delays for them to be able to identify where they are losing produce and attempt to minimise the losses as best as they can. Sensitivity analyses of the orange model showed that increasing entity arrival to 2 resulted in a doubling of throughput and increased resource utilisation. This proved that simulation models can be used to test alternative modelling scenarios without tampering with the actual system.