- C A M Zeeman and L Korsten
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria, 0002, South Africa
- 2007
Litchi (Litchi chinensis) export consignments travel in cold storage over long distances. Different cold storage facilities, both South African and international, were sampled in order to compare the degree of microbial contamination. Significantly higher numbers were found at the overseas facilities compared to the levels at local pack houses, particularly considering the numbers of fungi present. The predominant fungal genus was Penicillium, which can have both a saprophytic and pathogenic nature. It is therefore necessary to improve sanitation, especially at international storage facilities, in order to reduce post-harvest fruit decay due to excessive microbial inocula.
Summary:
- The study compared microbial contamination levels in air at South African litchi pack houses versus international cold storage and re-pack facilities.
- Significantly higher numbers of bacteria and fungi were found in international facilities compared to local pack houses, with fungal counts about five times higher.
- Penicillium species were the predominant fungi detected, known for both saprophytic and pathogenic characteristics, contributing to post-harvest fruit decay.
- Post-harvest litchi fruit is vulnerable to microbial contamination due to weakening of its natural defenses, especially during long-distance cold storage.
- Common post-harvest treatments like sulfur dioxide fumigation reduce microbial populations but also eliminate beneficial microbes, leaving fruit more susceptible to fungal infections.
- International storage facilities tend to be larger and handle mixed produce, increasing microbial diversity and contamination risk.
- Improved sanitation and alternating disinfection methods are necessary in these international facilities to reduce pathogen build-up and post-harvest losses.
- The microbial environment during storage significantly affects fruit quality, shelf life, and marketability.
- Fungal spores are well adapted to survive in post-harvest conditions due to their small size, abundance, and tolerance of low humidity and extreme temperatures.
- The study highlights the importance of managing the post-harvest environment to minimize decay and maintain export fruit quality.