Microbiological, proximate and heavy metal concentration in Penaeus sp. (shrimp) and Calllinectes sp. (crab) from creeks in Niger delta Nigeria

Microbial quality of Penaeus sp. and Callinectes sp. from Itu and Oron creeks in Niger Delta was investigated. The total bacteria population of samples varied from 1.60 x 10 ⁷ - 9.70 x 10 ⁸ cfu/g and 1.03 x 10 ⁷ - 8.90 x 10 ⁸ cfu/g for Penaeus sp. and Callinectes sp. from Itu and Oron creeks respectively. The results show that the samples contain unacceptable levels of bacteria with Penaeus sp. from Itu creek contaning up to 9.70 x 10 ⁸ cfu/g. The coliform levels were generally high ranged from 6.20 x 10 ⁷ - 9.40 x 10 ⁷ cfu/g and 5.30 x 10 ⁷ - 8.40 x x 10 ⁷ cfu/g for the samples. The Vibro count varied from 6.90 x 10 ⁷ - 8.20 x 10 ⁸ cfu/g and 5.20 - 5.90 x 10 ⁷ cfu/g for for the samples. The fungi count ranged from 3.10 - 3.70 x 10 ⁷ cfu/g and 3.20 - 4.00 x 10 ⁷ cfu/g. The bacteria isolates were E. coli, Streptococus sp. Serratia marcesens, Shigella sp, Bacllus sp, Vibrio sp. The fungi isolates were Aspergillus niger, Aspergillus terreus and Apergillus flavus. The total microbial counts obtained from this work were found to be higher than the specified standard limits (1x10 ⁵ cfu/g) for bacteria and fungi and 1.x10 ² cfu/g for coliforms) by ICMSF and USFDA. Proximate determination shows that samples from Oron creek were nutritionally richer than that from Itu creek. Percentage protein content for the two creeks ranged from 29.85 ^d to 54.13 ^a % in which Penaeus sp. from Oron creek significantly had the highest. Callinectes sp. from Oron creek had the highest Ca (0.94 ^a mg/kg), P (0.74 ^a mg/kg) and K (0.21 ^a mg/kg) content. The concentration of metal ranges of Fe, Mg, Zn, Pb, Cd, Mn and Cu in the samples were 17.2 ^d - 22.7 ^a mg/kg, 130 - 281 ^a mg/kg, 24.4 ^d - 94.2 ^a mg/kg, 0.28 ^d - 0.84 ^a mg/kg, 0.02 ^d - 0.15 ^a mg/kg, 24.2 ^d - 88.6 ^a mg/kg and 3.4 ^d - 7.4 ^a mg/kg respectively. Penaeus sp. from Oron creek had the highest concentration of metals except for Pb and Cd. It was observed that different metals were present in the samples at different levels but majority were found to be within the standard limits prescribed by EU and FAO. Crustacean from the creeks in Niger Delta though nutritionally rich harbor pathogenic microorganism and heavy metals which can pose a serious health hazard to consumers as they are not totally safe for human consumption.