Purpose: The aim of this study was to investigate the behavior of BC and GB during fermentation of cocoa beans.
Methods: Spores suspensions of five strains (each) of BC and GB were used. The fermentation process was performed using cocoa pods (Theobroma cacao L.) in a pilot scale (2 kg beans/box) for 7 days. In a daily basis, a different fermentation box was inoculated with 3 log CFU/g of BC and GB spores. During fermentation, samples were collected for microbiological, water activity and pH determinations. BC and GB were enumerated after heat shock (70ºC/15 min and 110ºC/10 min, respectively) on Mannitol Egg Yolk Polymyxin agar (MYP) and Dextrose Tryptone agar (DTA), respectively. Yeasts (YE), lactic acid bacteria (LAB) and acetic acid bacteria (AAC) were enumerated on Potato Dextrose Agar (PDA) + 10% tartaric acid, Man-Rogosa-Sharpe (MRS) + 50mg/L natamycin and PDA + 10% tartaric acid and 50 mg/L natamycin, respectively.
Results: The counts of BC and GB remained stable during the whole period of fermentation, except in the last two days of the process, in which increase in general, approximately 2.5 log CFU/g in populations of these bacteria were observed. This might be related to the increase of pH from 4.17 to 7.42 during fermentation, while water activity remained high (0.970). The inoculation of BC and GB spores in different days did not affect the fate of BC and GB. YE, LAB and AAC presented the behavior expected during fermentation of cocoa beans.
Significance: The fermentation process does not negatively influence on the counts of BC and GB in cocoa beans and thus, contamination of cocoa beans by spore-forming bacteria should be avoided.