Assessment of the Antimicrobial Properties of Ultraviolet Radiation Application and Different Types of Packaging during the Storage of Cocoa Beans

Aim: To assess ultraviolet radiation microbial deactivation and impact of different types of packaging during the storage of dried cocoa beans.

Study Design: Quasi experimental design.

Place and Duration of Study: Department of Microbiology, Faculty of Science, University of Yaoundé 1, between January 2023 and May 2024.

Methodology: Dried cocoa beans were used for ultraviolet radiation of 743.6 µW/cm² during 0 to 50 minutes. The total bacteria count, Enterobacteriaceae, Escherichia coli, yeasts, and moulds were enumerated, and the detection of Salmonella was performed. On the other hand, dried cocoa beans were introduced on 5 different packaging, and stored across two seasons, for 180 days and their microbial content and humidity assessed.

Results: The study observed that ultraviolet radiation type C with an intensity of 743.6 µW/cm² for 50 minutes reduces total bacteria count (TBC) by 1.62 log CFU/g (98%) and fungal flora by 2.03 log CFU/g (99%). Time of exposure was a significant factor affecting the ultraviolet antimicrobial efficacy. Based on Weibull model adaptation to experimental data, moulds were more sensitive to these radiation (b=0.09) than total bacteria count (b=0.0012). Hermetic bags show the ability to reduce microbial proliferation during the rainy and dry seasons compared to microaerophilic bags and Jute bags. The Hermetic bags also show an ability to resist humidification compared to microaerophilic bags packaging.

Conclusion: Ultraviolet radiation for 50 minutes and storage in hermetic packages of cocoa beans can be proposed as alternatives to the only jute bag storage commonly used today in the cocoa sector.