Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by
microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation
within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters.
However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of
cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study
investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented
under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The
resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared
with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii,
Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum,
Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and
Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the
presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic
acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where
the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp
and nibswere similar for beans fermented in the presence of lactic acid bacteria. Lactic acidwas produced during
both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of
lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no
differences in sensory rankings. It was concluded that lactic acid bacteria may not be necessary for successful
cocoa fermentation.