ISOLATION AND CHARACTERIZATION OF MICROORGANISMS INVOLVED IN THE FERMENTATION OF TRINIDAD'S CACAO BEANS

Abstract

In order to isolate, identify and characterize the microflora of cacao beans before, during and after fermentation and locate possible sources contributing to microbial contamination, cacao beans from the Centeno and San Louis Estates in Trinidad were investigated. Prior to fermentation, the interior and exterior of the pods, hands of employees, utensils, dried pulp material of the sweatboxes and finally fruitflies ( Drosophila melanogaster ) were studied microbiologically. At Centeno Estate, beans were sampled at 5, 45 and 90 cm depths at 8‐hr intervals for the first 72 hr and every 12 hr thereafter for 7 days. Sampling at San Louis Estate was carried out at 24 hr intervals for the same period. The changes in microbial population of the beans sampled at Centeno Estate ranged from 1.48 × 10 5 /g at 0 hr to 4.1 × 10 5 /g at the completion of the fermentation, whereas, at San Louis Estate they ranged from 6.8 × 10 5 /g to 9.2 × 10 5 /g during the same period. Taxonomical studies of isolates obtained during the fermentation period revealed the identification of 44 microorganisms at both Estates. Yeasts Zymomonas mobilis and several species of lactic acid organisms dominated the flora during the early stages of fermentation. As the fermentation progressed, these and other isolates were taken over by several species of genus Bacillus. Microbiological examination of dried and polished beans resulted in the identification of 22 organisms at Centeno Estate and 15 organisms at San Louis Estate