Isolation, identification and characterization of predominant microorganisims in Swazi traditional fermented porridge (incwancwa) and optimization of fermentation conditions Baphelele Khumalo 1 , W.K. Solomon 1* , T.H. Gadaga 2 , J.S. Shelembe 1 1 Department of Food, Nutrition and Technology, University of Eswatini 2 Department of Environmental Health Sciences, University of Eswatini *corresponding author wsolomon@uniswa.sz ; solowkj@yahoo.com Abstract The objective of the study was to isolate, identify and characterize the predominant microorganisms during the fermentation of incwancwa and optimize fermentation conditions. Samples were collected from six locations (three care points and three homesteads) using convenience sampling. Optimization of the fermentation time and temperature was carried out using response surface methodology and central composite design where graphical and numerical approaches were used. There was a significant (p<0.05) variation in the microbial load of samples collected from different sampling points. The lactic acid bacteria (LAB) load from fermented uncooked samples ranged from 4.6±1.46 to 6.56±0.2 logCFU/g whereas the load for yeast and coliforms ranged from 1.5±0.39 to 2.12±0.43 logCFU/g and 2.14±0.22 to 4.09±0.57 logCFU/g, respectively. The results indicated that LAB were the dominant microorganisms in incwancwa. Isolates were identified using Polymerase Chain Reaction (PCR) method by sequencing primers that bind to the 16S region of bacterial rDNA which revealed that Lueconostoc lactis, among other micro flora was the main LAB responsible for the unique properties in incwancwa. Sensory evaluation showed that fermentation time and temperature had significant (p<0.05) effect on the sensory perception of the product, the overall trend showed a greater chance of acceptance when the product was fermented at higher temperatures for longer periods. The best temperature and time range required to produce an acceptable product was found to be 32 o to 35 o C for 8 to 24 hours. Numerical optimization predicted that the preferred temperature and time combination was 35 o C for 15 hours. Keywords: fermentation, incwancwa, polymerase chain reaction, microorganisms. 1