Molecular Identification of Microbes Linked To Post-Harvest Deterioration of (Hibiscus sabdariffa L.) Roselle Calyx

Roselle (Hibiscus sabdariffa) is a popular crop known for its edible calyces, widely used in the food and beverage industry. However, the quality and shelf life of harvested roselle calyces is often compromised by various factors, including microbial contamination. Microbes play a significant role in the deterioration process, leading to changes in texture, color, and flavor and rendering the calyces unfit for consumption or commercial use. The collection and isolation of microorganisms from various states of calyces using techniques such as surface sterilization, serial dilution, and plating on selective media are employed to obtain pure cultures of microorganisms. These cultures are then subjected to a polymerase chain reaction (PCR) for 16S rRNA amplification and ITS region to detect bacterial and fungal populations. Sequencing analysis and BLAST identified fungal species, including Aspergillus ovarum, Meyerozyma amylolytica, and Meyerozyma guilliemondii. In contrast, the identified bacterial species were Providencia spp which was found to be the most prevalent bacterial species on roselle calyx. Generally, among the microbial diversity investigated, fungus species A. ovarum is more prevalent than bacterial species. Also, the most pervasive microbial diversity was detected in the deteriorated calyx. Both bacteria and fungi have been found to contaminate and facilitate the deterioration of the calyx, even though higher deterioration was detected caused by fungal isolates than bacterial isolates. In conclusion, the application of these molecular tools holds promise for improving the quality and marketability of roselle calyces in the future.