Evaluation of the microbiological quality of maboks smothered fish and, proteolytic activity of bacteria of the genus Bacillus in Brazzaville, Congo

In order to assess the health risks related to the consumption of smothered fish "mabokes" sold in the markets of Brazzaville, samples of smothered fish sold in three markets in Brazzaville were analyzed for their microbiological quality. The different samples were cultured for isolation on solid media using conventional microbiological methods. The bacteria isolated were identified on the basis of cultural, morphological and biochemical characteristics. At the end of this analysis, 79 bacteria were isolated, of which 29 (36.70%) at site 2, 25 (31.65%) at site 1 and 25 (31.65%) at site 3. Of the 79 strains, 46 (58.22%) were Gram-positive bacteria and 33 (41.78%) were Gram-negative bacteria. These strains consisted of 34 (43.03%) bacteria of the genus Bacillus, 12 (15.18%) bacteria of the genus Staphylococcus and 33 (41.79%) Enterobacteria including 15 bacteria of the genus Shigella. The enumeration results show that the average value of the total flora varies from 2.90.108±1.5.107 CFU/ml (Site 2) to 5.55.109±2.107CFU/ml (Site 3), that of Bacillus between 1.30.107±1.41.106 CFU/ml (Site 2) and 7.85. 107± 1.02.106 CFU/ml (Site 3), for Staphylococcus between 1.44.106±2.02. 106CFU/ml (Site 1) and 6.17.106±8.25.106CFU/ml (Site 2). The average value of Enterobacteriaceae ranges from 70.104±2.4.104 CFU/ml (Site 2) to 9.15.105±1.29.104 CFU/mL (Site 3) and from 0 (Site 3) to 5.65.104±7.85.104 CFU/ml (Site 1) for Shigella. Proteolytic enzyme production was observed in 9 out of 12 selected strains. Although these smothered fish have strains with proteolytic activity, the presence of Staphylococcus and Enterobacteriaceae make this food unfit for consumption.   Key words: Microbiological quality, fish, smothered, proteolytic activity.